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Title:
AKARI Near- and Mid-Infrared Spectroscopy of APM 08279+5255 at z = 3.91
Authors:
Oyabu, S.; Kawara, K.; Tsuzuki, Y.; Matsuoka, Y.; Sameshima, H.; Asami, N.; Ohyama, Y.
Affiliation:
AA(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yosinodai, Sagamihara, Kanagawa 229-8510, Japan ), AB(Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan ), AC(System Integration Service Department, Redfox Inc., 3-3-11, Kita-Aoyama, Minato-ku, Tokyo 107-0061, Japan ), AD(Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan ; Research Fellow of the Japan Society for the Promotion of Science. ; Present address: Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.), AE(Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan ), AF(Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan ), AG(Academia Sinica, Institute of Astronomy and Astrophysics, Taiwan )
Publication:
The Astrophysical Journal, Volume 697, Issue 1, pp. 452-457 (2009). (ApJ Homepage)
Publication Date:
05/2009
Origin:
IOP
ApJ Keywords:
galaxies: active, infrared: galaxies, quasars: emission lines, quasars: general, quasars: individual: APM 08279+5255
DOI:
10.1088/0004-637X/697/1/452
Bibliographic Code:
2009ApJ...697..452O

Abstract

We present rest-frame optical/near-infrared spectra of the gravitationally lensed quasar APM 08279+5255 at z = 3.91 that has been taken using the Infrared Camera (IRC) onboard the AKARI infrared satellite. The observed continuum consists of two components; a power-law component dominating optical wavelengths which is the direct light from the central source and thermal emission dominating near-infrared wavelengths which is attributed to the emission from hot dust in the circumnuclear region. The thermal emission well represents optically thick emission by hot dust at T ~ 1300 K with τ2 μm > 2 and apparent mass, M hot > 10 M sun. Thus, our observations directly detected the optically thick region of hot dust in APM 08279+5255. H I recombination lines of Hα (0.656 μm), Paα (1.875 μm), and Paβ (1.282 μm) are clearly detected at 3.2, 6.3, and 9.3 μm. Simulations with the photoionization models suggest that APM 08279+5255 has broad-line region (BLR) clouds characterized by log n H ~ 12-14 for the gas density, log U ~ -2 to -6 for the ionization parameter, and E(B - V) ~ 0.3-0.6 for the BLR. Thus, optically thick emission of hot dust supports an idea on nonspherical distribution of dust near the central source, consistent with the active galactic nuclei model with the dust torus. The temperature of hot dust and flux ratios of these H I lines are similar to those observed in low-redshift quasars. There are significant time variations in the H I lines, which are probably caused by variations in the brightness of the central source.

Based on observations with AKARI, a JAXA project with the participation of ESA.



Title:
Properties of Newly Formed Dust by SN 2006JC Based on Near- to Mid-Infrared Observation With AKARI
Authors:
Sakon, I.; Onaka, T.; Wada, T.; Ohyama, Y.; Kaneda, H.; Ishihara, D.; Tanabé, T.; Minezaki, T.; Yoshii, Y.; Tominaga, N.; Nomoto, K.; Nozawa, T.; Kozasa, T.; Tanaka, M.; Suzuki, T.; Umeda, H.; Ohyabu, S.; Usui, F.; Matsuhara, H.; Nakagawa, T.; Murakami, H.
Affiliation:
AA(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ), AB(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ), AC(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan ), AD(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan ; Current Address: Institute of Astronomy, and Astrophysics Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan. ), AE(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan ; Current Address: Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan. ), AF(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ), AG(Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Ohsawa, Mitaka, Tokyo 181-0015, Japan ), AH(Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Ohsawa, Mitaka, Tokyo 181-0015, Japan ), AI(Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Ohsawa, Mitaka, Tokyo 181-0015, Japan ), AJ(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ; Current Address: Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan. ), AK(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ; Current Address: Institute for the Physics and Mathematics for the Universe, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568, Japan.), AL(Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan ; Current Address: Institute for the Physics and Mathematics for the Universe, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568, Japan.), AM(Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan ), AN(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ; Current Address: Institute for the Physics and Mathematics for the Universe, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568, Japan.), AO(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ), AP(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan ), AQ(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan ), AR(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan ), AS(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan ), AT(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan ), AU(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan )
Publication:
The Astrophysical Journal, Volume 692, Issue 1, pp. 546-555 (2009). (ApJ Homepage)
Publication Date:
02/2009
Origin:
IOP
ApJ Keywords:
dust, extinction, infrared: ISM, stars: Wolf-Rayet, supernovae: general, supernovae: individual: SN2006jc
DOI:
10.1088/0004-637X/692/1/546
Bibliographic Code:
2009ApJ...692..546S

Abstract

We present our latest results on near- to mid-infrared (MIR) observation of supernova (SN) 2006jc at 200 days after the discovery using the Infrared Camera (IRC) on board AKARI. The near-infrared (2-5 μm) spectrum of SN 2006jc is obtained for the first time and is found to be well interpreted in terms of the thermal emission from amorphous carbon of 800 ± 10 K with the mass of 6.9 ± 0.5 × 10-5 M sun that was formed in the SN ejecta. This dust mass newly formed in the ejecta of SN 2006jc is in a range similar to those obtained for other several dust-forming core-collapse supernovae based on recent observations (i.e., 10-3-10-5 M sun). MIR photometric data with AKARI/IRC MIR-S/S7, S9W, and S11 bands have shown excess emission over the thermal emission by hot amorphous carbon of 800 K. This MIR excess emission is likely to be accounted for by the emission from warm amorphous carbon dust of 320 ± 10 K with the mass of 2.7+0.7 -0.5 × 10-3 M sun rather than by the band emission of astronomical silicate and/or silica grains. This warm amorphous carbon dust is expected to have been formed in the mass-loss wind associated with the Wolf-Rayet stellar activity before the SN explosion. Our result suggests that a significant amount of dust is condensed in the mass-loss wind prior to the SN explosion.


Title:
Galaxy Clusters at 0.9 < z < 1.7 in the AKARI NEP Deep Field
Authors:
Goto, Tomotsugu; Hanami, Hitoshi; Im, Myungshin; Imai, Koji; Inami, Hanae; Ishigaki, Tsuyoshi; Lee, Hyung Mok; Matsuhara, Hideo; Nakagawa, Takao; Ohyama, Youichi; Oyabu, Shinki; Pearson, Chris P.; Takagi, Toshinobu; Wada, Takehiko
Affiliation:
AA(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI, 96822, USA; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588; ) AB(Physics Section, Faculty of Humanities and Social Sciences, Iwate University, Morioka, Iwate 020-8550) AC(Department of Physics and Astronomy, FPRD, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea) AD(TOME R&D Inc., 3-2-1 Sakado, Kawasaki, Kanagawa 213-0012) AE(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510; Department of Space and Astronautical Science, School of Physical Science, The Graduate University for Advanced Studies (ISAS/JAXA), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AF(Asahikawa National College of Technology, 2-1-6 2-jo Shunkohdai, Asahikawa, Hokkaido 071-8142) AG(Department of Physics and Astronomy, FPRD, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea) AH(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AI(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AJ(Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan, Republic of China) AK(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AL(ISO Data Centre, ESA, Villafranca del Castillo, Apartado 50727, 28080 Madrid, Spain) AM(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AN(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510)
Publication:
Publications of the Astronomical Society of Japan, Vol.60, No.SP2, pp.S531--S542 (PASJ Homepage)
Publication Date:
12/2008
Origin:
PASJ
Keywords:
galaxies: clusters: general, galaxies: evolution, galaxies: formation
Bibliographic Code:
2008PASJ...60S.531G

Abstract

There is ahuge gap between the properties of red-sequence selected massive galaxy clusters at z < 1 and Lyman-break selected proto-clusters at z > 3. It is important to understand when and how the z > 3 proto-clusters evolve into passive clusters at z < 1. We aim to fill this cluster desert by using space-based N4 (4 μm) imaging with AKARI. The z' ‑ N4 color is apowerful separator of cluster galaxies at z > 1, taking advantage of the 4000Å break and the 1.6 μm bump. We carefully selected 16 promising cluster candidates at 0.9 < z < 1.7, which all show an obvious over-density of galaxies and aprominent red-sequence. At this redshift range, the mid-infrared S15μm / S9μm flux ratio is an extinction-free indicator of galaxy star-formation activity due to the redshifted PAH emission lines (6.2, 7.7, and 8.6 μm). We show statistically that the cluster galaxies have alower S15μm / S9μm flux ratio than do field galaxies, i.e., cluster galaxies already have lower star-formation activity at 0.9 < z < 1.7, pushing the formation epoch of these galaxy clusters to a higher redshift.


Title:
AKARI/IRC Deep Survey in the North Ecliptic Pole Region
Authors:
Wada, Takehiko; Matsuhara, Hideo; Oyabu, Shinki; Takagi, Toshinobu; Lee, Hyung Mok; Im, Myungshin; Ohyama, Youichi; Goto, Tomotsugu; Pearson, Chris P.; White, Glenn J.; Serjeant, Stephen; Wada, Kensuke; Hanami, Hitoshi
Affiliation:
AA(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229 8510) AB(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229 8510) AC(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229 8510) AD(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229 8510) AE(Department of Physics & Astronomy, FPRD, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea) AF(Department of Physics & Astronomy, FPRD, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea) AG(Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan) AH(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA) AI(Rutherford Appleton Laboratory, Oxon, OX11 0QX, UK; Department of Physics, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1J 1B1, Canada ) AJ(Department of Physics & Astronomy, The Open University, Milton Keynes, MK7 6AA, UK; Rutherford Appleton Laboratory, Oxon, OX11 0QX, UK.) AK(Department of Physics & Astronomy, The Open University, Milton Keynes, MK7 6AA, UK) AL(Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551; Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229 8510) AM(Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550)
Publication:
Publications of the Astronomical Society of Japan, Vol.60, No.SP2, pp.S517--S529 (PASJ Homepage)
Publication Date:
12/2008
Origin:
PASJ
Keywords:
galaxies : evolution, galaxies : statistics, infrared galaxies, space vehicles: instruments
Bibliographic Code:
2008PASJ...60S.517W

Abstract

We have made adeep and wide imaging survey with all nine AKARI/IRC bands from 2 to 24 μm within ahalf degree of the North Ecliptic Pole. The survey covered acircular area of 0.38deg2 centered at RA = 17h56m, Dec = 66°37' where adeep optical multi-band survey has been conducted by Subaru/Suprime-Cam. The 5σ sensitivity of the survey for point sources is 11.0, 48, 117, and 275 μJy at wavelengths 3, 7, 15, and 24 μm, respectively. The survey is limited by sky noise at wavelengths from 7 to 24 μm, and limited by source confusion from 2 to 4 μm. We have also made apoint source catalog at each band, consisting of more than 5000 sources with a 50% completeness limit of 93 μ Jy at 15 μm. Our results are consistent with the pilot survey at faint fluxes and has better statistical significance at the bright fluxes. This is the first near- and mid-infrared sub-mJy extragalactic survey with contiguous wavelength coverage from 2 to 24 μm and a large band-merged catalogue. It will provide powerful and unique diagnostics of obscured star-formation and AGN activities in the galaxies up to z = 2.


Title:
Systematic Infrared 2.5-5 μm Spectroscopy of Nearby Ultraluminous Infrared Galaxies with AKARI
Authors:
Imanishi, Masatoshi; Nakagawa, Takao; Ohyama, Yoichi; Shirahata, Mai; Wada, Takehiko; Onaka, Takashi; Oi, Nagisa
Affiliation:
AA(National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588; ) AB(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AC(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AD(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AE(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AF(Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033) AG(Department of Astronomy, School of Science, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588)
Publication:
Publications of the Astronomical Society of Japan, Vol.60, No.SP2, pp.S489--S515 (PASJ Homepage)
Publication Date:
12/2008
Origin:
PASJ
Keywords:
galaxies: active, galaxies: ISM, galaxies: nuclei, infrared: galaxies
Bibliographic Code:
2008PASJ...60S.489I

Abstract

We report on the results of systematic infrared 2.5-5 μm spectroscopy of 45 nearby ultraluminous infrared galaxies (ULIRGs) at z < 0.3 using AKARI IRC. This paper investigates whether the luminosities of these ULIRGs are dominated by starburst activity, or alternatively, whether optically elusive buried active galactic nuclei (AGNs) are energetically important, based on the strengths of 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission and dust absorption features at 3-4 μm. Because of the AKARI IRC's spectroscopic capability in the full 2.5-5 μm wavelength range, we can apply this energy diagnostic method to ULIRGs at z > 0.15. We estimate the intrinsic luminosities of extended (several kpc), modestly obscured (AV < 15 mag) starburst activity based on the observed 3.3 μm PAH emission luminosities measured in AKARI IRC slitless spectra, and confirm that such starbursts are energetically unimportant in nearby ULIRGs. In roughly half of the observed ULIRGs classified optically as non-Seyferts, we find signatures of luminous buried AGNs. The fraction of ULIRGs with detectable buried AGN signatures increases with increasing infrared luminosity. Our overall results support the scenario that luminous buried AGNs are important in many ULIRGs at z < 0.3 classified optically as non-Seyferts, and that the optical undetectability of such buried AGNs occurs merely because of alarge amount of nuclear dust, which can make the sightline of even the lowest dust column density opaque to the ionizing radiation of the AGNs.


Title:
Absolute Photometric Calibration of the Infrared Camera (IRC) aboard AKARI
Authors:
Tanabé, Toshihiko; Sakon, Itsuki; Cohen, Martin; Wada, Takehiko; Ita, Yoshifusa; Ohyama, Youichi; Oyabu, Shinki; Uemizu, Kazunori; Takagi, Toshinobu; Ishihara, Daisuke; Kim, Woojung; Ueno, Munetaka; Matsuhara, Hideo; Onaka, Takashi
Affiliation:
AA(Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015; ) AB(Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033) AC(Radio Astronomy Laboratory, 601 Campbell Hall, University of California, Berkeley, CA 94720, USA) AD(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AE(National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588) AF(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AG(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AH(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AI(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AJ(Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033) AK(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AL(Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902) AM(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510) AN(Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033)
Publication:
Publications of the Astronomical Society of Japan, Vol.60, No.SP2, pp.S375--S388 (PASJ Homepage)
Publication Date:
12/2008
Origin:
PASJ
Keywords:
infrared: general, space vehicles: instruments, techniques: photometric
Bibliographic Code:
2008PASJ...60S.375T

Abstract

The absolute photometric calibration of imaging observations with the Infrared Camera (IRC) aboard the AKARI satellite was performed by monitoring the same stars regularly and by observing aset of standard stars. By our monitoring observations, we confirmed that all channels of the IRC were stable to within 4% and that their sensitivities were constant until the liquid helium was exhausted. Using the data of these repeated observations, we evaluated the intrinsic errors as afunction of the brightnesses of objects and found that the errors increase rapidly toward fainter objects. We also checked the consistency between short and long exposure times, and confirmed that the data sampling had been executed as designed. Finally, by comparing the estimated in-band flux densities and the observed data values of standard stars, we obtained conversion factors to the absolute flux densities of all the band/exposure configurations. Their absolute uncertainties are estimated to be less than 6%.


Title:
Multi-Wavelength Analysis of 18 μm-Selected Galaxies in the AKARI/Infrared-Camera monitor fieldtowards the North Ecliptic Pole
Authors:
Takagi, T.; Matsuhara, H.; Wada, T.; Oyabu, S.; Imai, K.; Pearson, C. P.; Hanami, H.; Onaka, T.; Fujishiro, N.; Ishihara, D.; Ita, Y.; Kataza, H.; Kim, W.; Matsumoto, T.; Murakami, H.; Ohyama, Y.; Sakon, I.; Tanabé, T.; Uemizu, K.; Ueno, M.; Watarai, H.; Usui, F.; Lee, H. M.; Im, M.; Serjeant, S.; Savage, R. S.; Tange, T.; Nakagawa, T.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S557 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.557T

Abstract

We present an initial analysis of AKARI 18z Ultra-Luminous InfraRed Galaxies, and a large variation of the PAH inter-band strength ratio in galaxies at high redshifts.


Title:
Optical Identification of 15 μm Sources in the AKARI Performance Verification Field toward the North Ecliptic Pole
Authors:
Matsuhara, H.; Wada, T.; Pearson, C. P.; Oyabu, S.; Im, M.; Imai, K.; Takagi, T.; Kang, E.; Hwang, N.; Jeong, W.-S.; Lee, H. M.; Lee, M. G.; Pak, S.; Serjeant, S.; Nakagawa, T.; Hanami, H.; Inami, H.; Onaka, T.; Fujishiro, N.; Ishihara, D.; Ita, Y.; Kataza, H.; Kim, W.; Matsumoto, T.; Murakami, H.; Ohyama, Y.; Sakon, I.; Tanabé, T.; Uemizu, K.; Ueno, M.; Watarai, H.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S543 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.543M

Abstract

We present the results of optical identifications for 257 mid-infrared sources detected with a deep 15K_{s}


Title:
Nature of Infrared Sources in 11 μm Selected Sample from Early Data of the AKARI North Ecliptic Pole Deep Survey
Authors:
Lee, H. M.; Im, M.; Wada, T.; Shim, H.; Kim, S. J.; Lee, M. G.; Hwang, N.; Matsuhara, H.; Nakagawa, T.; Oyabu, S.; Pearson, C. P.; Takagi, T.; Onaka, T.; Fujishiro, N.; Hanami, H.; Ishihara, D.; Ita, Y.; Kataza, H.; Kim, W.; Matusmoto, T.; Murakami, H.; Ohyama, Y.; Sakon, I.; Tanabé, T.; Uemizu, K.; Ueno, M.; Usui, F.; Watarai, H.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S529 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.529L

Abstract

We present the properties of 11 10^{12} L_{ȯ} based on detailed modelling of the SEDs. We also find four AGNs lying at various redshifts in the main sample. In addition, we discuss a few sources that have non-typical SEDs of the main sample, including a brown-dwarf candidate, a steep power-law source, a flat-spectrum object, and an early-type galaxy at moderate redshift.


Title:
Infrared Camera (IRC) Deep Survey in the Performance-Verification Phase
Authors:
Wada, T.; Oyabu, S.; Ita, Y.; Matsuhara, H.; Pearson, C. P.; Onaka, T.; Ohyama, Y.; Usui, F.; Fujishiro, N.; Ishihara, D.; Kataza, H.; Kim, W.; Matsumoto, T.; Murakami, H.; Sakon, I.; Tanabé, T.; Takagi, T.; Uemizu, K.; Ueno, M.; Watarai, H.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S515 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.515W

Abstract

We report on the first results of a near- and mid-infrared deep survey with the Infrared Camera (IRC) onboard AKARI in the performance-verification phase. Simultaneous observations by the Near-InfraRed (NIR), Mid-InfraRed Short (MIR-S), and Mid-InfraRed Long (MIR-L) channels of the IRC with effective integration times of 4529, 4908, and 4417 seconds at 3, 7, and 15μm raw source counts agrees with those from deep surveys in the GOODS fields, carried out with the Spitzer IRS peak up imager and predictions of current galaxy evolution models. These results indicate that deep surveys with comprehensive wavelength coverage at mid-infrared wavelength are very important to investigate the evolution of infrared galaxies at high redshifts.


Title:
Detection of an Hα Emission Line on a Quasar, RX J1759.4+6638, at z = 4.3 with AKARI
Authors:
Oyabu, S.; Wada, T.; Ohyama, Y.; Matsuhara, H.; Takagi, T.; Nakagawa, T.; Onaka, T.; Fujishiro, N.; Ishihara, D.; Ita, Y.; Kataza, H.; Kim, W.; Matsumoto, T.; Murakami, H.; Sakon, I.; Tanabé, T.; Uemizu, K.; Ueno, M.; Usui, F.; Watarai, H.; Haze, K.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S497 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.497O

Abstract

We report on the detection of an Hα) is consistent with those of previous reports for lower-redshift quasars.


Title:
Properties of UIR Bands in NGC6946 Based on Mid-Infrared Imaging and Spectroscopy with Infrared Camera on Board AKARI
Authors:
Sakon, I.; Onaka, T.; Wada, T.; Ohyama, Y.; Matsuhara, H.; Kaneda, H.; Ita, Y.; Ohyabu, S.; Kataza, H.; Fujishiro, N.; Ihara, C.; Ishigaki, M.; Ishihara, D.; Kim, W.; Okada, Y.; Takagi, T.; Tanabé, T.; Uemizu, K.; Ueno, M.; Usui, F.; Watarai, H.; Koo, B.-C.; Serjeant, S.; Nakagawa, T.; Matsumoto, T.; Murakami, H.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S483 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.483S

Abstract

We present results on mid-infrared imaging and spectroscopic observations of the nearby late-type spiral NGC6946 with the Infrared Camera on board AKARI. Based on mid-infrared imaging with the S7 (7μm may be tools to measure the star-formation activity in remote galaxies if these ratios and their variations are well examined and established for a large sample.


Title:
AKARI Infrared Imaging of Reflection Nebulae IC4954 and IC4955
Authors:
Ishihara, D.; Onaka, T.; Kaneda, H.; Suzuki, T.; Kataza, H.; Sakon, I.; Okada, Y.; Doi, Y.; Fujishiro, N.; Fujiwara, H.; Ita, Y.; Kii, T.; Kim, W.; Makiuti, S.; Matsumoto, T.; Matsuhara, H.; Murakami, H.; Nakagawa, T.; Ohyama, Y.; Oyabu, S.; Stephen, S.; Shibai, H.; Takagi, T.; Tanabé, T.; Uemizu, K.; Ueno, M.; Usui, F.; Wada, T.; Watarai, H.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S443 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.443I

Abstract

We present the observations of the reflection nebulae IC4954 and IC4955 region with the Infrared Camera and the Far-Infrared Surveyor (FIS) on board the infrared astronomical satellite AKARI during its performance verification phase. We obtained 7 band images from 7 to 1601° around the IC4954/4955 region was created from the AKARI mid-infrared All-Sky Survey data. Together with the HI 21cm data, it suggests a large hollow structure of a degree scale, on whose edge the IC4954/4955 region has been created, indicating star formation over three generations in largely different spatial scales.


Title:
AKARI Observations of Circumstellar Dust in the Globular Clusters NGC 104 and NGC 362
Authors:
Ita, Y.; Tanabé, T.; Matsunaga, N.; Nakada, Y.; Matsuura, M.; Onaka, T.; Matsuhara, H.; Wada, T.; Fujishiro, N.; Ishihara, D.; Kataza, H.; Kim, W.; Matsumoto, T.; Murakami, H.; Ohyama, Y.; Usui, F.; Oyabu, S.; Sakon, I.; Takagi, T.; Uemizu, K.; Ueno, M.; Watarai, H.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S437 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.437I

Abstract

We report on preliminary results of AKARI observations of two globular clusters, NGC 104 and NGC 362. Imaging data covering areas of about 10 F_{7} ratio being greater than unity in NGC 362. Six out of the eight have no 2MASS counterparts. However, we found no such source in NGC 104.


Title:
Near-Infrared and Mid-Infrared Spectroscopy with the Infrared Camera (IRC) for AKARI
Authors:
Ohyama, Y.; Onaka, T.; Matsuhara, H.; Wada, T.; Kim, W.; Fujishiro, N.; Uemizu, K.; Sakon, I.; Cohen, M.; Ishigaki, M.; Ishihara, D.; Ita, Y.; Kataza, H.; Matsumoto, T.; Murakami, H.; Oyabu, S.; Tanabé, T.; Takagi, T.; Ueno, M.; Usui, F.; Watarai, H.; Pearson, C. P.; Takeyama, N.; Yamamuro, T.; Ikeda, Y.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S411 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.411O

Abstract

The Infrared Camera (IRC) is one of the two instruments on board the AKARI satellite. In addition to deep imaging from 1.8 to 26.5 ×


Title:
The Infrared Camera (IRC) for AKARI -- Design and Imaging Performance
Authors:
Onaka, T.; Matsuhara, H.; Wada, T.; Fujishiro, N.; Fujiwara, H.; Ishigaki, M.; Ishihara, D.; Ita, Y.; Kataza, H.; Kim, W.; Matsumoto, T.; Murakami, H.; Ohyama, Y.; Oyabu, S.; Sakon, I.; Tanabé, T.; Takagi, T.; Uemizu, K.; Ueno, M.; Usui, F.; Watarai, H.; Cohen, M.; Enya, K.; Ootsubo, T.; Pearson, C. P.; Takeyama, N.; Yamamuro, T.; Ikeda, Y.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S401 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.401O

Abstract

The Infrared Camera (IRC) is one of two focal-plane instruments on the AKARI satellite. It is designed for wide-field deep imaging and low-resolution spectroscopy in the near- to mid-infrared (1.8-26.5'


Title:
The Infrared Astronomical Mission AKARI
Authors:
Murakami, H.; Baba, H.; Barthel, P.; Clements, D. L.; Cohen, M.; Doi, Y.; Enya, K.; Figueredo, E.; Fujishiro, N.; Fujiwara, H.; Fujiwara, M.; Garcia-Lario, P.; Goto, T.; Hasegawa, S.; Hibi, Y.; Hirao, T.; Hiromoto, N.; Hong, S. S.; Imai, K.; Ishigaki, M.; Ishiguro, M.; Ishihara, D.; Ita, Y.; Jeong, W.-S.; Jeong, K. S.; Kaneda, H.; Kataza, H.; Kawada, M.; Kawai, T.; Kawamura, A.; Kessler, M. F.; Kester, D.; Kii, T.; Kim, D. Chan; Kim, W.; Kobayashi, H.; Koo, B. C.; Kwon, S. M.; Lee, H. M.; Lorente, R.; Makiuti, S.; Matsuhara, H.; Matsumoto, T.; Matsuo, H.; Matsuura, S.; Müller, T. G.; Murakami, N.; Nagata, H.; Nakagawa, T.; Naoi, T.; Narita, M.; Noda, M.; Oh, S. H.; Ohnishi, A.; Ohyama, Y.; Okada, Y.; Okuda, H.; Oliver, S.; Onaka, T.; Ootsubo, T.; Oyabu, S.; Pak, S.; Park, Y.-S.; Pearson, C. P.; Rowan-Robinson, M.; Saito, T.; Sakon, I.; Salama, A.; Sato, S.; Savage, R. S.; Serjeant, S.; Shibai, H.; Shirahata, M.; Sohn, J.; Suzuki, T.; Takagi, T.; Takahashi, H.; Tanabé, T.; Takeuchi, T. T.; Takita, S.; Thomson, M.; Uemizu, K.; Ueno, M.; Usui, F.; Verdugo, E.; Wada, T.; Wang, L.; Watabe, T.; Watarai, H.; White, G. J.; Yamamura, I.; Yamauchi, C.; Yasuda, A.
Publication:
Publications of the Astronomical Society of Japan, Vol.59, No.s2, p. S369 (PASJ Homepage)
Publication Date:
10/2007
Origin:
PASJ
Bibliographic Code:
2007PASJ...59S.369M

Abstract

AKARI, the first Japanese satellite dedicated to infrared astronomy, was launched on 2006 February 21, and started observations in May of the same year. AKARI has a 68.5 cm cooled telescope, together with two focal-plane instruments, which survey the sky in six wavelength bands from mid- to far-infrared. The instruments also have a capability for imaging and spectroscopy in the wavelength range 2-180μm in the pointed observation mode, occasionally inserted into a continuous survey operation. The in-orbit cryogen lifetime is expected to be one and a half years. The All-Sky Survey will cover more than 90% of the whole sky with a higher spatial resolution and a wider wavelength coverage than that of the previous IRAS all-sky survey. Point-source catalogues of the All-Sky Survey will be released to the astronomical community. Pointed observations will be used for deep surveys of selected sky areas and systematic observations of important astronomical targets. These will become an additional future heritage of this mission.


Title:
Deep Extragalactic Surveys around the Ecliptic Poles with AKARI (ASTRO-F)
Authors:
Matsuhara, Hideo; Wada, Takehiko; Matsuura, Shuji; Nakagawa, Takao; Kawada, Mitsunobu; Ohyama, Youichi; Pearson, Chris P.; Oyabu, Shinki; Takagi, Toshinobu; Serjeant, Stephen; White, Glenn J.; Hanami, Hitoshi; Watarai, Hidenori; Takeuchi, Tsutomu T.; Kodama, Tadayuki; Arimoto, Nobuo; Okamura, Sadanori; Lee, Hyung Mok; Pak, Soojong; Im, Myung Shin; Lee, Myung Gyoon; Kim, Woojung; Jeong, Woong-Seob; Imai, Koji; Fujishiro, Naofumi; Shirahata, Mai; Suzuki, Toyoaki; Ihara, Chiaki; Sakon, Itsuki
Affiliation:
AA(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ; ) AB(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AC(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AD(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AE(Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602) AF(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AG(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ;ISO Data Centre, ESA, Villafranca del Castillo, Madrid, Spain) AH(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AI(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ;University of Kent, Canterbury, Kent CT2 7NR, UK) AJ(University of Kent, Canterbury, Kent CT2 7NR, UK;Astrophysics Group, Department of Physics, The Open University, Milton Keynes, MK7 6AA, UK) AK(University of Kent, Canterbury, Kent CT2 7NR, UK;Astrophysics Group, Department of Physics, The Open University, Milton Keynes, MK7 6AA, UK) AL(Iwate University, 3-18-8 Ueda, Morioka 020-8550) AM(Office of Space Applications, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki 305-8505) AN(Laboratoire d'Astrophysique de Marseille, Traverse du Siphon, BP8 13376 Marseille Cedex 12, France;Astronomical Institute, Tohoku University, Aoba-ku, Sendai 980-8578) AO(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588) AP(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588) AQ(Department of Astronomy, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033) AR(Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea) AS(Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Korea) AT(Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea) AU(Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea) AV(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AW(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AX(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AY(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) AZ(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) BA(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) BB(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 ) BC(Department of Astronomy, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033)
Publication:
Publications of the Astronomical Society of Japan, Vol.58, No.4, pp.673-694 (PASJ Homepage)
Publication Date:
08/2006
Origin:
PASJ
Keywords:
galaxies: evolution, galaxies: statistics, infrared: galaxies, space vehicles: instruments
Bibliographic Code:
2006PASJ...58..673M

Abstract

AKARI (formerly ASTRO-F) is an infrared space telescope designed for an all-sky survey at 10-180 μm, and deep pointed surveys of selected areas at 2-180 μm. The deep pointed surveys with AKARI will significantly advance our understanding of galaxy evolution, the structure formation of the universe, the nature of buried AGNs, and the cosmic infrared background. We describe here the important characteristics of the AKARI mission, the orbit, and attitude control system, and investigate the optimum survey area based on the updated pre-flight sensitivities of AKARI, taking into account the cirrus confusion noise as well as the surface density of bright stars. The North Ecliptic Pole is concluded to be the best area for 2-26μm deep surveys, while the low-cirrus noise regions around the South Ecliptic Pole are worth considering for 50-180μm pointed surveys to high sensitivities limited by the galaxy confusion noise. Current observational plans concerning these pointed surveys are described in detail. Comparing these surveys with deep surveys using the Spitzer Space Telescope, the AKARI deep surveys are particularly unique in respect of their continuous wavelength coverage over the 2-26μm range in broad-band deep imaging, and their slitless spectroscopy mode over the same wavelength range.


Title:
Low- and Medium-Dispersion Spectropolarimetry of Nova V475 Scuti (Nova Scuti 2003): Discovery of an Asymmetric High-Velocity Wind in a Moderately Fast Nova
Authors:
Kawabata, Koji S.; Ohyama, Youichi; Ebizuka, Noboru; Takata, Tadafumi; Yoshida, Michitoshi; Isogai, Mizuki; Norimoto, Yuji; Okazaki, Akira; Saitou, Masashi S.
Affiliation:
AA(Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan; .), AB(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720; , .; Department of Infrared Astrophysics, Institute of Space and Aeronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan.), AC(Integrated V-CAD System Research Program, RIKEN, Wako, Saitama 351-0198, Japan; .), AD(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720; , .; Astronomical Data Analysis Center, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AE(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, 3037-5 Honjo, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan; , .), AF(Kiso Observatory, Institute of Astronomy, University of Tokyo, Mitake-mura, Kiso-gun, Nagano 397-0101, Japan; .), AG(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, 3037-5 Honjo, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan; , .), AH(Department of Science Education, Gunma University, Aramaki 4-2, Maebashi 371-8510, Japan; , .), AI(Department of Science Education, Gunma University, Aramaki 4-2, Maebashi 371-8510, Japan; , .)
Publication:
The Astronomical Journal, Volume 132, Issue 1, pp. 433-442. (AJ Homepage)
Publication Date:
07/2006
Origin:
UCP
AJ Keywords:
Stars: Circumstellar Matter, Stars: Novae, Cataclysmic Variables, Polarization, stars: individual (V475 Scuti), Stars: Winds, Outflows
DOI:
10.1086/505040
Bibliographic Code:
2006AJ....132..433K

Abstract

We present low-resolution (R~90) and medium-resolution (R~2500) spectropolarimetry of nova V475 Sct taken with the HBS instrument, mounted on the 0.91 m telescope at the Okayama Astrophysical Observatory, and taken with the Faint Object Camera and Spectrograph, mounted on the 8.2 m Subaru telescope. We estimated the interstellar polarization toward the nova from the steady continuum polarization components and Hα line emission components. After subtracting the interstellar polarization component from the observations, we found that the Hα emission seen on 2003 October 7 was clearly polarized. In the polarized flux spectrum the Hα emission had a distinct red wing extending to ~+4900 km s-1 and a shoulder around +3500 km s-1, showing a constant position angle (P.A.) of linear polarization θ*~=155deg+/-15deg. This suggests that the nova had an asymmetric outflow with a velocity of vwind~=3500 km s-1 or more, which is 6 times higher than the expansion velocity of the ionized shell at the same epoch. Such a high-velocity component has not previously been reported for a nova in the ``moderately fast'' speed class. Our observations suggest the occurrence of violent mass-loss activity in the nova binary system even during the common-envelope phase. The P.A. of the polarization in the Hα wing is in good agreement with that of the continuum polarization found on 2003 September 26 (p*~=0.4%-0.6%), which disappeared within the following 2 days. The uniformity of the P.A. between the continuum polarization and the wing polarization on October 7 suggests that the axis of the circumstellar asymmetry remained nearly constant during the period of our observations.

Based on data obtained at the Subaru telescope and the Okayama Astrophysical Observatory, which are operated by the National Astronomical Observatory of Japan.



Title:
Near-Infrared Search for C IV Absorption Counterparts along the Lines of Sight to Pair Quasars
Authors:
Misawa, Toru; Kashikawa, Nobunari; Ohyama, Youichi; Hashimoto, Tetsuya; Iye, Masanori
Affiliation:
AA(Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802; .), AB(National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomical Science, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AC(Department of Infrared Astrophysics, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan.), AD(Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.), AE(National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomical Science, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.)
Publication:
The Astronomical Journal, Volume 131, Issue 1, pp. 34-40. (AJ Homepage)
Publication Date:
01/2006
Origin:
UCP
AJ Keywords:
Galaxies: Evolution, Galaxies: Quasars: Absorption Lines, quasars: individual (Q0301-005), Galaxies: Quasars: Individual: Alphanumeric: Q0302-003, quasars: individual (KP 76), quasars: individual (KP 77), quasars: individual (KP 78), Galaxies: Quasars: Individual: Alphanumeric: Q2343+125, quasars: individual (Q2344+125)
DOI:
10.1086/498270
Bibliographic Code:
2006AJ....131...34M

Abstract

We carried out a Subaru and UKIRT near-infrared imaging survey for Hα-emitting galaxies around two pair quasar systems (Q0301-005/Q0302-003 and Q2343+125/Q2344+125) and a triple quasar system (KP 76/KP 77/KP 78). Narrowband near-infrared filters covering the Hα emission expected for galaxies at the confirmed C IV absorption redshift toward the quasar systems were used for this survey. These quasar pairs or triplet are separated at most by 17' (~5 h-1 Mpc in proper distance) from each other on the sky and have common C IV absorption lines at almost identical redshifts at z=2.24-2.43, which suggests there could be a megaparsec-scale absorbing system such as a cluster, or a group, of galaxies that covers all the lines of sight to the pair/triple quasars. Using narrowband deep images, we detected five candidates for Hα-emitting galaxies around two of the six fields, Q2343+125 and Q2344+125, whose apparent star formation rates are extremely high, 20-466 Msolar yr-1. However, all or most of them are not likely to be galaxies at the absorption redshift but galaxies at lower redshift, because of their extreme brightness. In the fields of the other quasars, we detected no star-forming galaxies, nor did we find any number excess of galaxy counts around them. These nondetections could be because the luminosities and star formation rates of galaxies are lower than the detection limits of our observations (K'>21 and SFR<1.8-240 h-2 Msolar yr-1). They could be located outside of the observed field around Q0301 and Q0302, since our targeting field covers only 2% of this pair quasar field. But this is not the case for the other pair/triple quasar fields, because we found large field coverage fractions (~33%-75%). Otherwise, most C IV absorption lines could be ascribed not to clusters of galaxies but to isolated star-forming pockets, far from bright galaxies, that could be analogous objects to weak Mg II absorbers.

Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan

Based on data collected at the United Kingdom Infrared Telescope (UKIRT), which is operated by the Joint Astronomy Centre on behalf of the UK Particle Physics and Astronomy Research Council.



Title:
Subaru Imaging and Spectroscopy of Globular Cluster Candidates around M82
Authors:
Saito, Yoshihiko; Ohyama, Youichi; Yoshida, Michitoshi; Sasaki, Toshiyuki; Kosugi, George; Kashikawa, Nobunari; Takata, Tadafumi; Shimizu, Yasuhiro; Inata, Motoko; Okita, Kiichi; Aoki, Kentaro; Sekiguchi, Kaz; Kawabata, Koji S.; Asai, Ryo; Taguchi, Hiroko; Ebizuka, Noboru; Yadoumaru, Yasushi; Ozawa, Tomohiko; Iye, Masanori
Affiliation:
AA(National Astronomical Observatory Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AB(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AC(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Okayama, 719-0232, Japan.), AD(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AE(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AF(National Astronomical Observatory Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AG(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AH(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Okayama, 719-0232, Japan.), AI(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Okayama, 719-0232, Japan.), AJ(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Okayama, 719-0232, Japan.), AK(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AL(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AM(National Astronomical Observatory Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AN(Systems Engineering Consultants, Co., LTD., Shibuya-ku, Tokyo, 150-0031, Japan.), AO(Waseda Jitsugyo, 1-2-1 Honcho, Kokubunji, Tokyo, 185-8505, Japan.), AP(The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan.), AQ(Misato Observatory, 180 Matsugamine, Misato, Wakayama, 640-1366, Japan.), AR(Misato Observatory, 180 Matsugamine, Misato, Wakayama, 640-1366, Japan.), AS(National Astronomical Observatory Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.; Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588, Japan.)
Publication:
The Astrophysical Journal, Volume 621, Issue 2, pp. 750-756. (ApJ Homepage)
Publication Date:
03/2005
Origin:
UCP
ApJ Keywords:
Galaxies: Evolution, Galaxies: Individual: Messier Number: M82, Galaxies: Star Clusters, Galaxies: Starburst, Galaxy: Globular Clusters: General
DOI:
10.1086/427645
Bibliographic Code:
2005ApJ...621..750S

Abstract

We carried out a search for globular clusters in M82 by taking advantage of the relatively high resolution imaging and deep spectroscopic capabilities provided by the Faint Object Camera And Spectograph (FOCAS) on the Subaru Telescope. Since M82 is a late-type galaxy, its globular cluster system provides a basis for comparison with the globular cluster system of our Galaxy or that of M31. The archetypal starburst galaxy M82 also constitutes an ideal target for studying the relation between galaxy interactions, starbursts, and globular cluster formation. First, we performed an imaging survey to pick up globular cluster candidates using the color-magnitude selection method. Follow-up spectroscopic observations were carried out for 29 globular cluster candidates using the multiobject spectroscopic mode of FOCAS. In the central 6' diameter region of M82, we found two bona fide globular clusters and three young star clusters in our first attempt at optical searching for globular clusters in M82. The estimated age of young star clusters is <~1 Gyr, which is consistent with or lower than the age derived by infrared photometry. Two bona fide globular clusters should have formed at the epoch of M82's formation. Some of the young star clusters identified in M82 are likely to have been produced during the tidal-interaction episode with M81.

Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.



Title:
The SUBARU Deep Field Project: Lymanα Emitters at a Redshift of 6.6
Authors:
Taniguchi, Yoshiaki; Ajiki, Masaru; Nagao, Tohru; Shioya, Yasuhiro; Murayama, Takashi; Kashikawa, Nobunari; Kodaira, Keiichi; Kaifu, Norio; Ando, Hiroyasu; Karoji, Hiroshi; Akiyama, Masayuki; Aoki, Kentaro; Doi, Mamoru; Fujita, Shinobu S.; Furusawa, Hisanori; Hayashino, Tomoki; Iwamuro, Fumihide; Iye, Masanori; Kobayashi, Naoto; Kodama, Tadayuki; Komiyama, Yutaka; Matsuda, Yuichi; Miyazaki, Satoshi; Mizumoto, Yoshihiko; Morokuma, Tomoki; Motohara, Kentaro; Nariai, Kyoji; Ohta, Koji; Ohyama, Youichi; Okamura, Sadanori; Ouchi, Masami; Sasaki, Toshiyuki; Sato, Yasunori; Sekiguchi, Kazuhiro; Shimasaku, Kazuhiro; Tamura, Hajime; Umemura, Masayuki; Yamada, Toru; Yasuda, Naoki; Yoshida, Michitoshi
Affiliation:
AA(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), AC(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578; INAF -- Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy), AD(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), AE(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), AF(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AG(The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa 240-0193), AH(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AI(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AJ(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), AK(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), AL(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), AM(Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015), AN(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), AO(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), AP(Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), AQ(Department of Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-8502), AR(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AS(Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015), AT(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AU(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), AV(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588; Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), AW(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), AX(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AY(Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015), AZ(Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015), BA(Department of Physics, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-8506), BB(Department of Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-8502), BC(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), BD(Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033; Research Center for the Early Universe, Graduate School of Science, The University of Tokyo, Tokyo 113-0033), BE(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), BF(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), BG(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), BH(Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720, USA), BI(Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033), BJ(Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578), BK(Center for Computational Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571), BL(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), BM(Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582), BN(Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232)
Publication:
Publications of the Astronomical Society of Japan, Vol.57, No.1, pp. 165-182 (PASJ Homepage)
Publication Date:
02/2005
Origin:
PASJ
Keywords:
cosmology: observations, early universe, galaxies: formation, galaxies: evolution, galaxies: starburst
Bibliographic Code:
2005PASJ...57..165T

Abstract

We present new results of a deep optical imaging survey using a narrow band filter (NB921) centered at λ = 9196 Å together with B, V, R, i', and z' broadband filters in the sky area of the Subaru Deep Field, which has been promoted as one of legacy programs of the 8.2m Subaru Telescope. We obtained a photometric sample of 58 Ly α emitter candidates at z ≈ 6.5‑6.6 among ˜ 180 strong NB921-excess (z' ‑ NB921 > 1.0) objects together with a color criterion of i' ‑ z' > 1.3. We then obtained optical spectra of 20 objects in our NB921-excess sample, and identified at least nine Ly α emitters at z ˜ 6.5‑6.6, including the two emitters reported by Kodaira et al. (2003, PASJ, 55, L17). Since our Ly α-emitter candidates are free from strong amplification of gravitational lensing, we are able to discuss their observational properties from a statistical point of view. Based on these new results, we obtained a lower limit of the star-formation rate density of ρSFR ≃ 5.7 × 10-4 h0.7 M ȯ yr-1 Mpc-3 at z ≈ 6.6, being consistent with our previous estimate. We discuss the nature of star-formation activity in galaxies beyond z = 6.


Title:
Subaru Deep Spectroscopy of a Star-forming Companion Galaxy of BR 1202-0725 at z=4.7
Authors:
Ohyama, Youichi; Taniguchi, Yoshiaki; Shioya, Yasuhiro
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, Hilo, HI 96720.), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AC(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.)
Publication:
The Astronomical Journal, Volume 128, Issue 6, pp. 2704-2711. (AJ Homepage)
Publication Date:
12/2004
Origin:
UCP
AJ Keywords:
Galaxies: Starburst, Galaxies: Quasars: Individual: Alphanumeric: BR 1202-0725
DOI:
10.1086/425887
Bibliographic Code:
2004AJ....128.2704O

Abstract

We present deep spatially resolved optical spectroscopy of the northwest companion galaxy of the quasar BR 1202-0725 at z=4.7. Its rest-frame UV spectrum shows star-forming activity in the nuclear region. The Lyα emission profile is symmetric with wavelength, while its line width is unusually wide (FWHM~=1100 km s-1) for such a high-z star-forming galaxy. The spectrum taken along the Lyα nebula elongation, which is almost along the minor axis of the companion host galaxy, reveals that off-nuclear Lyα nebulae have either flat-topped or multipeaked profiles along the extension. All these properties can be understood in terms of superwind activity in the companion galaxy. We also find a diffuse continuum component around the companion, which shows a morphology similar to that of Lyα nebula, and is most likely due to scattering of the quasar light at a dusty halo around the companion. We argue that the superwind could expel dusty material out to the halo region, making a dusty halo for scattering.

Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.



Title:
Subaru Spectropolarimetry of Markarian 573: The Hidden High-Ionization Nuclear Emission-Line Region inside the Dusty Torus
Authors:
Nagao, Tohru; Kawabata, Koji S.; Murayama, Takashi; Ohyama, Youichi; Taniguchi, Yoshiaki; Shioya, Yasuhiro; Sumiya, Ryoko; Sasaki, Shunji S.
Affiliation:
AA(Osservatorio Astrofisico di Arcetri, INAF, Largo Enrico Fermi 5, I-50125 Florence, Italy; .; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AB(Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.), AC(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AD(Subaru Telescope, NAOJ, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AE(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AF(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AG(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AH(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.)
Publication:
The Astronomical Journal, Volume 128, Issue 5, pp. 2066-2072. (AJ Homepage)
Publication Date:
11/2004
Origin:
UCP
AJ Keywords:
Galaxies: Active, Galaxies: Individual: Name: Markarian 573, Galaxies: Nuclei, Galaxies: Seyfert, Polarization
DOI:
10.1086/424936
Bibliographic Code:
2004AJ....128.2066N

Abstract

We report the results of our high-quality spectropolarimetric observation of the narrow-line region in a nearby Seyfert 2 galaxy, Mrk 573, with the Subaru Telescope. The polarized flux spectrum of Mrk 573 shows not only prominent scattered broad Hα emission but also various narrow forbidden emission lines. We find that the measured polarization degree of the observed forbidden emission lines is positively correlated with the ionization potential of the corresponding ions and the critical density of the corresponding transitions. We discuss some possible origins of these correlations, and then we point out that the correlations are caused by the obscuration of the stratified narrow-line region in Mrk 573 by the optically and geometrically thick dusty torus, matching findings of a previous study of NGC 4258.

Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan (NAOJ).



Title:
Detection of the Polarized Broad Emission Line in the Seyfert 2 Galaxy Markarian 573
Authors:
Nagao, Tohru; Kawabata, Koji S.; Murayama, Takashi; Ohyama, Youichi; Taniguchi, Yoshiaki; Sumiya, Ryoko; Sasaki, Shunji S.
Affiliation:
AA(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AB(Department of Physical Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.), AC(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AD(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AE(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AF(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AG(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.)
Publication:
The Astronomical Journal, Volume 128, Issue 1, pp. 109-114. (AJ Homepage)
Publication Date:
07/2004
Origin:
UCP
AJ Keywords:
Galaxies: Active, galaxies: individual (Mrk 573), Galaxies: Nuclei, Galaxies: Seyfert, Polarization
DOI:
10.1086/421740
Bibliographic Code:
2004AJ....128..109N

Abstract

We report the discovery of the scattered emission from a hidden broad-line region (BLR) in a Seyfert 2 galaxy, Mrk 573, based on our recent spectropolarimetric observation performed at the Subaru Telescope. This object has been regarded as a type 2 active galactic nucleus (AGN) without a hidden BLR by previous observations. However, our high-quality spectrum of the polarized flux of Mrk 573 shows prominent broad (~3000 km s-1) Hα emission, broad weak Hβ emission, and subtle Fe II multiplet emission. Our new detection of these indications for the presence of the hidden BLR in the nucleus of Mrk 573 is thought to be because of the high signal-to-noise ratio of our data, but the possibility of a time variation of the scattered BLR emission is also mentioned. Some diagnostic quantities such as the IRAS color, the radio power, and the line ratio of the emission from the narrow-line region of Mrk 573 are consistent with the distributions of such quantities of type 2 AGNs with a hidden BLR. Mrk 573 is thought to be an object whose level of the AGN activity is the weakest among the type 2 AGNs with a hidden BLR. In terms of the systematic differences between the type 2 AGNs with and without a hidden BLR, we briefly comment on an interesting Seyfert 2 galaxy, Mrk 266 SW, which may possess a hidden BLR but has been treated as a type 2 AGNs without a hidden BLR.

Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.



Title:
Current Performance and On-Going Improvements of the 8.2 m Subaru Telescope
Authors:
Iye, Masanori; Karoji, Hiroshi; Ando, Hiroyasu; Kaifu, Norio; Kodaira, Keiichi; Aoki, Kentaro; Aoki, Wako; Chikada, Yoshihiro; Doi, Yoshiyuki; Ebizuka, Noboru; Elms, Brian; Fujihara, Gary; Furusawa, Hisanori; Fuse, Tetsuharu; Gaessler, Wolfgang; Harasawa, Sumiko; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko; Ichikawa, Shinichi; Imanishi, Masatoshi; Ishida, Catherine; Kamata, Yukiko; Kanzawa, Tomio; Kashikawa, Nobunari; Kawabata, Koji; Kobayashi, Naoto; Komiyama, Yutaka; Kosugi, George; Kurakami, Tomio; Letawsky, Michael; Mikami, Yoshitaka; Miyashita, Akihiko; Miyazaki, Satoshi; Mizumoto, Yoshihiko; Morino, Junichi; Motohara, Kentaro; Murakawa, Koji; Nakagiri, Masao; Nakamura, Kyoko; Nakaya, Hidehiko; Nariai, Kyoji; Nishimura, Tetsuo; Noguchi, Kunio; Noguchi, Takeshi; Noumaru, Takeshi; Ogasawara, Ryusuke; Ohshima, Norio; Ohyama, Yoichi; Okita, Kiichi; Omata, Koji; Otsubo, Masashi; Oya, Shin; Potter, Robert; Saito, Yoshihiko; Sasaki, Toshiyuki; Sato, Shuji; Scarla, Dennis; Schubert, Kiaina; Sekiguchi, Kazuhiro; Sekiguchi, Maki; Shelton, Ian; Simpson, Chris; Suto, Hiroshi; Tajitsu, Akito; Takami, Hideki; Takata, Tadafumi; Takato, Naruhisa; Tamae, Richard; Tamura, Motohide; Tanaka, Wataru; Terada, Hiroshi; Torii, Yasuo; Uraguchi, Fumihiko; Usuda, Tomonori; Weber, Mark; Winegar, Tom; Yagi, Masafumi; Yamada, Toru; Yamashita, Takuya; Yamashita, Yasumasa; Yasuda, Naoki; Yoshida, Michitoshi; Yutani, Masami
Affiliation:
AA(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588; ), AB(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AC(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), AD(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AE(Department of Astronomy, Graduate University for Advanced Studies, Hayama, Kanagawa 240-0193), AF(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AG(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), AH(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AI(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AJ(The Institute of Physical and Chemical Research, RIKEN, Wako, Saitama 351-0198), AK(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AL(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AM(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AN(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AO(Max-Plank für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany), AP(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AQ(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), AR(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AS(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AT(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), AU(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), AV(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AW(Advanced Technology Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588), AX(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), AY(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), AZ(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), BA(Institute of Astronomy, School of Science, The University of Tokyo, Mitaka, Tokyo 181-8588), BB(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BC(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BD(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BE(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BF(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), BG(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BH(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BI(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), BJ(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BK(Institute of Astronomy, School of Science, The University of Tokyo, Mitaka, Tokyo 181-8588), BL(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BM(Department of Astronomy, Graduate University for Advanced Studies, Hayama, Kanagawa 240-0193), BN(Advanced Technology Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588), BO(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BP(Department of Physics, Meisei University, Hino, Tokyo 191-8506), BQ(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BR(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), BS(290-2 Izawa, Misaki-cho, Isumi-gun, Chiba 299-4615), BT(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BU(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BV(Advanced Technology Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588), BW(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BX(Okayama Astrophysical Observatory, National Astronomical Observatory, Asakuchi-gun, Okayama 719-0232), BY(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), BZ(Advanced Technology Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588), CA(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CB(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CC(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), CD(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CE(Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602), CF(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CG(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CH(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CI(5-5-22-201 Sekimae, Musashino, Tokyo 180-0014), CJ(David Dunlap Observatory, 123 Hillsview Drive, Richmond Hill, Ontario, L4C 1T3 Canada), CK(Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK), CL(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CM(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CN(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CO(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CP(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CQ(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CR(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), CS(4-4-23 Takatanobaba, Shinjuku-ku, Tokyo 160-0075), CT(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CU(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), CV(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CW(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CX(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CY(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), CZ(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), DA(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), DB(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720, USA), DC(1-14-12 Asahigaoka, Hino, Tokyo 191-0065), DD(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588), DE(Okayama Astrophysical Observatory, National Astronomical Observatory, Asakuchi-gun, Okayama 719-0232), DF(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588)
Publication:
Publications of the Astronomical Society of Japan, Vol.56, No.2, pp. 381-397 (PASJ Homepage)
Publication Date:
04/2004
Origin:
PASJ
Keywords:
telescopes: instruments
Bibliographic Code:
2004PASJ...56..381I

Abstract

An overview of the current status of the 8.2m Subaru Telescope constructed and operated at Mauna Kea, Hawaii, by the National Astronomical Observatory of Japan is presented. The basic design concept and the verified performance of the telescope system are described. Also given are the status of the instrument package offered to the astronomical community, the status of operation, and some of the future plans. The status of the telescope reported in a number of SPIE papers as of the summer of 2002 are incorporated with some updates included as of 2004 February. However, readers are encouraged to check the most updated status of the telescope through the home page, http://subarutelescope.org/index.html, and/or the direct contact with the observatory staff.


Title:
Subaru Spectroscopy of the Interacting Type Ia Supernova SN 2002ic: Evidence of a Hydrogen-rich, Asymmetric Circumstellar Medium
Authors:
Deng, J.; Kawabata, K. S.; Ohyama, Y.; Nomoto, K.; Mazzali, P. A.; Wang, L.; Jeffery, D. J.; Iye, M.; Tomita, H.; Yoshii, Y.
Affiliation:
AA(Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; .; Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AB(Department of Physical Sciences, Hiroshima University, Hiroshima 739-8526, Japan.; Optical and Infrared Astronomy Division, National Astronomical Observatory of Japan, 2-21-1 Ohsawa, Mitaka, Tokyo 181-8588, Japan.), AC(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, Hilo, HI 96720.), AD(Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; .; Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AE(Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; .; Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.; INAF-Osservatorio Astronomico, Via Tiepolo 11, 34131 Trieste, Italy.), AF(Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720.), AG(Department of Physics, University of Nevada at Las Vegas, Box 454002, Las Vegas, NV 89154.), AH(Optical and Infrared Astronomy Division, National Astronomical Observatory of Japan, 2-21-1 Ohsawa, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomy, Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588, Japan.), AI(Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AJ(Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; .; Institute of Astronomy, University of Tokyo, Mitaka, Tokyo 181-0015, Japan.)
Publication:
The Astrophysical Journal, Volume 605, Issue 1, pp. L37-L40. (ApJ Homepage)
Publication Date:
04/2004
Origin:
UCP
ApJ Keywords:
Stars: Supernovae: General, Stars: Supernovae: Individual: Alphanumeric: SN 2002ic
DOI:
10.1086/420698
Bibliographic Code:
2004ApJ...605L..37D

Abstract

Optical spectroscopy of the Type Ia supernova SN 2002ic obtained on 2003 June 27.6 UT, i.e., ~222 rest-frame days after explosion, is presented. Strong H emission indicates an interaction between the expanding SN ejecta and an H-rich circumstellar medium (CSM). The spectrum of SN 2002ic resembles those of SNe 1997cy and 1999E. The three SNe also have similar luminosities, suggesting that they are the same phenomenon and that the CSM is also similar. We propose a new classification, Type IIa SNe, for these events. The observed line profiles and line ratios are measured and discussed within the ejecta-CSM interaction scenario. The emission in H Balmer, [O III], and He I lines, and in permitted Fe II blends, resembles the spectra of the Type IIn SN 1987F and of Seyfert 1 galaxies. A high-density, clumpy CSM is inferred. Strong, very broad [Ca II]/Ca II and [O I]/O I emissions imply that not all the outer SN ejecta were decelerated in the interaction, suggesting that the CSM is aspherical.


Title:
Subaru Spectroscopy of the Giant Lyα Nebula Associated with the High-z Powerful Radio Galaxy 1243+036
Authors:
Ohyama, Youichi; Taniguchi, Yoshiaki
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.)
Publication:
The Astronomical Journal, Volume 127, Issue 3, pp. 1313-1317. (AJ Homepage)
Publication Date:
03/2004
Origin:
UCP
AJ Keywords:
Galaxies: Evolution, Galaxies: Formation, galaxies: individual (PKS 1243+036), Galaxies: Starburst
Bibliographic Code:
2004AJ....127.1313O

Abstract

We report results of our new spatially resolved, optical spectroscopy of the giant Lyα nebula around a powerful radio galaxy, 1243+036 (4C +03.24), at z=3.57. The nebula is extended over ~30 kpc from the nucleus and forms a pair of cones or elongated bubbles. The high-velocity (roughly -1000 km s-1 blueshifted with respect to the systemic velocity) Lyα-emitting components are detected at both sides of the nucleus along its major axis. The northwestern nebula is more spectacular in its velocity shift (blueshifted by -1000 to -1400 km s-1) and in its width (~=1900 km s-1 FWHM) over ~=30 kpc scale. We discuss possible origins of the nebula, such as (1) a shock-heated expanding bubble or outflowing cone associated with the superwind activity of the host galaxy, (2) halo gas photoionized by the anisotropic radiation from the active galactic nuclei (AGNs), and (3) a jet-induced star formation or shock. The last possibility may not be likely because Lyα emission is distributed out of the narrow channel of the radio jet. We show that the superwind model is most plausible since it can explain both the characteristics of the morphology (size and shape) and the kinematical structures (velocity shift and line width) of the nebula although the photoionization by AGNs may contribute to the excitation to some extent.

Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.



Title:
Spectral Evolution of the GRB 030329 Afterglow: Detection of the Supernova Nebular Phase Emissions
Authors:
Kosugi, George; Mizumoto, Yoshihiko; Kawai, Nobuyuki; Yoshida, Atsumasa; Kawabata, Koji S.; Totani, Tomonori; Iye, Masanori; Sekiguchi, Kazuhiro; Aoki, Kentaro; Ohyama, Youichi; Aoki, Wako; Kobayashi, Naoto; Komiyama, Yutaka; Noumaru, Jun'ichi; Ogasawara, Ryusuke; Sakamoto, Takanori; Shirasaki, Yuji; Takata, Tadafumi; Tamagawa, Toru; Torii, Ken'ichi; Urata, Yuji; Watanabe, Jun-Ichi; Yamada, Toru; Qiu, Yulei
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA ; ), AB(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AC(Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-0033;Cosmic Radiation Laboratory, RIKEN, Wako, Saitama 351-0198), AD(Cosmic Radiation Laboratory, RIKEN, Wako, Saitama 351-0198;Department of Physics, Aoyama Gakuin University, Sagamihara, Kanagawa 229-8558), AE(Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526), AF(Department of Astronomy, Kyoto University, Sakyo-ku, Kyoto 606-8502), AG(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AH(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA), AI(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA), AJ(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA), AK(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AL(Institute of Astronomy, The University of Tokyo, Mitaka, Tokyo 181-8588), AM(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA), AN(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA), AO(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA), AP(Cosmic Radiation Laboratory, RIKEN, Wako, Saitama 351-0198), AQ(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AR(Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720, USA), AS(Cosmic Radiation Laboratory, RIKEN, Wako, Saitama 351-0198), AT(Cosmic Radiation Laboratory, RIKEN, Wako, Saitama 351-0198), AU(Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-0033;Cosmic Radiation Laboratory, RIKEN, Wako, Saitama 351-0198), AV(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AW(National Astronomical Observatory, Mitaka, Tokyo 181-8588), AX(National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China)
Publication:
Publications of the Astronomical Society of Japan, Vol.56, No.1, pp. 61-68 (PASJ Homepage)
Publication Date:
02/2004
Origin:
PASJ
Keywords:
cosmology: early universe, gamma rays: bursts, gamma rays: individual (GRB 030329), gamma rays: observations, stars: supernovae: individual (SN 2003dh)
Bibliographic Code:
2004PASJ...56...61K

Abstract

GRB 030329 is the first Gamma-ray burst event for which a connection with a supernova (SN 2003dh) has been confirmed spectroscopically in its early phase. We present optical spectroscopy of this object 40 and 85 days after the burst (35 and 73 rest-frame days, respectively) obtained with the Subaru 8.2-m telescope. After subtracting the host galaxy template spectrum, the second-epoch spectrum shows nebular-phase emission lines emerging from the dominated photospheric-phase spectrum. The transition from the photospheric phase to the nebular phase has just started, or was slowly progressing at the time of our second-epoch observations. Our spectral analysis of the nebular-phase emission lines suggests that the explosion of the progenitor of the GRB 030329 was aspherical, and that the axis of an asphericity is well aligned to both the GRB relativistic jet and our line of sight. Although the decay index and the color evolution in the rest frame during our two epochs are very consistent with those of the Type Ic supernovae SN 1998bw and SN 1997ef, the nebular-phase lines emerged slightly earlier than in the case of these supernovae. These results infer that the most important factor that distinguishes SNe with GRB from SNe without GRB is the scale of the jet activity, or a viewing-angle effect, or both of them.


Title:
Subaru Deep Spectroscopy of the Very Extended Emission-Line Region of NGC 4388: Ram Pressure Stripped Gas Ionized by Nuclear Radiation
Authors:
Yoshida, Michitoshi; Ohyama, Youichi; Iye, Masanori; Aoki, Kentaro; Kashikawa, Nobunari; Sasaki, Toshiyuki; Shimasaku, Kazuhiro; Yagi, Masafumi; Okamura, Sadanori; Doi, Mamoru; Furusawa, Hisanori; Hamabe, Masaru; Kimura, Masahiko; Komiyama, Yutaka; Miyazaki, Masayuki; Miyazaki, Satoshi; Nakata, Fumiaki; Ouchi, Masami; Sekiguchi, Maki; Yasuda, Naoki
Affiliation:
AA(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.; Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232, Japan; .), AB(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`Ohoku Place, Hilo, HI 96720.), AC(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AD(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`Ohoku Place, Hilo, HI 96720.), AE(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AF(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`Ohoku Place, Hilo, HI 96720.), AG(Department of Astronomy, University of Tokyo, Tokyo 113-0033, Japan.), AH(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AI(Department of Astronomy, University of Tokyo, Tokyo 113-0033, Japan.), AJ(Institute of Astronomy, University of Tokyo, Mitaka, Tokyo 181-8588, Japan.), AK(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`Ohoku Place, Hilo, HI 96720.; Department of Astronomy, University of Tokyo, Tokyo 113-0033, Japan.), AL(Department of Mathematical and Physical Sciences, Japan Women's University, Bunkyo-ku, Tokyo 112-8681, Japan.), AM(Department of Astronomy, Kyoto University, Kyoto 606-8502, Japan.), AN(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`Ohoku Place, Hilo, HI 96720.), AO(Department of Astronomy, University of Tokyo, Tokyo 113-0033, Japan.), AP(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`Ohoku Place, Hilo, HI 96720.), AQ(Department of Astronomy, University of Tokyo, Tokyo 113-0033, Japan.), AR(Department of Astronomy, University of Tokyo, Tokyo 113-0033, Japan.), AS(Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan.), AT(Astronomical Data Analysis Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.)
Publication:
The Astronomical Journal, Volume 127, Issue 1, pp. 90-104. (AJ Homepage)
Publication Date:
01/2004
Origin:
UCP
AJ Keywords:
Galaxies: Clusters: General, Galaxies: Evolution, Galaxies: Individual: NGC Number: NGC 4388, Galaxies: Kinematics and Dynamics, Galaxies: Seyfert, Galaxies: Intergalactic Medium
DOI:
10.1086/380221
Bibliographic Code:
2004AJ....127...90Y

Abstract

We report here the results of deep optical spectroscopy of the very extended emission-line region (VEELR) found serendipitously around the Seyfert 2 galaxy NGC 4388 in the Virgo Cluster using the Subaru Telescope. The Hα recession velocities of most of the filaments of the region observed are highly blueshifted with respect to the systemic velocity of the galaxy. The velocity field is complicated, and from the kinematic and morphological points of view, there seem to be several streams of filaments: low-velocity filaments, with radial velocities v with respect to the systemic velocity of NGC 4388 of roughly -100 km s-1 high-velocity (v~-300 km s-1) filaments; and a very high velocity (v~-500 km s-1) cloud complex. The emission-line ratios of the VEELR filaments are well explained by power-law photoionization models with solar abundances, suggesting that the Seyfert nucleus of NGC 4388 is the dominant ionization source of the VEELR and that the VEELR gas has moderate metallicity. In addition to photoionization, shock heating probably contributes to the ionization of the gas. In particular, the filaments outside the ionization cone of the Seyfert nucleus are mainly excited by shocks. The predicted shock velocity is ~200-300 km s-1, which is comparable to the velocities of the filaments. We conclude that the VEELR was formerly the disk gas of NGC 4388, which has been stripped by ram pressure due to the interaction between the hot intracluster medium and the galaxy. The velocity field and the morphology of the VEELR closely resemble snapshots from some numerical simulations of this process. In the case of NGC 4388, the ram pressure stripped gas, which is normally seen as extended H I filaments, happens to be exposed and ionized by the radiation from the active galactic nucleus, and so can be seen as optical emission-line gas.

Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.



Title:
Superwind-driven Intense H2 Emission in NGC 6240. II. Detailed Comparison of Kinematic and Morphological Structures of the Warm and Cold Molecular Gas
Authors:
Ohyama, Youichi; Yoshida, Michitoshi; Takata, Tadafumi
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720), AB(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan), AC(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720)
Publication:
The Astronomical Journal, Volume 126, Issue 5, pp. 2291-2298. (AJ Homepage)
Publication Date:
11/2003
Origin:
UCP
AJ Keywords:
Galaxies: Individual: NGC Number: NGC 6240, Galaxies: Interactions, Galaxies: Intergalactic Medium,
DOI:
10.1086/378709
Bibliographic Code:
2003AJ....126.2291O

Abstract

We report on our new analysis of the spatial and kinematic distribution of warm and cold molecular gas in the nearby, prototypical, luminous infrared galaxy NGC 6240, which was undertaken to explore the origin of its unusually luminous H2 emission. The gas components are known to be distributed between the two merging nuclei, forming an off-nuclear molecular gas concentration. By comparing three-dimensional emission-line data (in space and velocity) of CO J=2-1 in the radio and H2 in the near-infrared, we are able to search for the spatial and kinematic conditions under which efficient H2 emission is produced in much more detail than has previously been possible. In particular, we focus on the H2-emitting efficiency, defined in terms of the intensity ratio of H2 to CO [I(H2)/I(CO)], as a function of velocity. We derive this by utilizing the recent high-resolution, three-dimensional data presented by Tecza and coworkers. The integrated H2-emitting efficiency is calculated by integrating the velocity profile of H2-emitting efficiency in blue, red, and total (blue plus red) velocity regions of the profile. We find that (1) both the total H2-emitting efficiency and the blue-to-red ratio of the efficiency are larger in regions surrounding the CO and H2 intensity peaks, and (2) the H2-emitting efficiency and the kinematic conditions in the warm molecular gas are closely related to each other. We compare two possible models that might explain these characteristics: a large-scale collision between the molecular gas concentration and the merging nuclei, and a collision between the molecular gas concentration and the external superwind outflow from the south nucleus. The latter model seems more plausible, since it can reproduce the enhanced emitting efficiency of blueshifted H2 around the molecular gas concentration if we assume that the superwind blows from the south nucleus toward us, hitting the entire gas concentration from behind. In this model, internal cloud-cloud collisions within the molecular gas concentration are enhanced by the interaction with the superwind outflow, and efficient and intense shock-excited H2 emission is expected as a result of the cloud-crushing mechanism. The observed spatial distribution of the H2-emitting efficiency can be explained if there is a greater kinematic disturbance in the outer part of the molecular gas concentration, as a result of the interaction with the superwind outflow, and also more frequent cloud-cloud collisions in the region. In addition, the kinematic influence of the superwind on the molecular gas concentration should be larger at bluer velocities, and the collision frequency is expected to be larger at bluer velocities, explaining the relationship between velocity and the H2-emitting efficiency.


Title:
On the Spectrum and Spectropolarimetry of Type Ic Hypernova SN 2003dh/GRB 030329
Authors:
Kawabata, K. S.; Deng, J.; Wang, L.; Mazzali, P.; Nomoto, K.; Maeda, K.; Tominaga, N.; Umeda, H.; Iye, M.; Kosugi, G.; Ohyama, Y.; Sasaki, T.; Höflich, P.; Wheeler, J. C.; Jeffery, D. J.; Aoki, K.; Kashikawa, N.; Takata, T.; Kawai, N.; Sakamoto, T.; Urata, Y.; Yoshida, A.; Tamagawa, T.; Torii, K.; Aoki, W.; Kobayashi, N.; Komiyama, Y.; Mizumoto, Y.; Noumaru, J.; Ogasawara, R.; Sekiguchi, K.; Shirasaki, Y.; Totani, T.; Watanabe, J.; Yamada, T.
Affiliation:
AA(Optical and Infrared Astronomy Division, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , , , , , .), AB(Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; , , , , , .; Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AC(Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720; .), AD(Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; , , , , , .; Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.; INAF-Osservatorio Astronomico, Via Tiepolo 11, 34131 Trieste, Italy.), AE(Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; , , , , , .; Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AF(Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; , , , , , .; Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AG(Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; , , , , , .; Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AH(Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; , , , , , .; Research Center for the Early Universe, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.), AI(Optical and Infrared Astronomy Division, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , , , , , .; Department of Astronomy, Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588, Japan.), AJ(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), AK(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), AL(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), AM(Department of Astronomy, University of Texas at Austin, RLM 15.308, C-1400, Austin, TX 78712; , .), AN(Department of Astronomy, University of Texas at Austin, RLM 15.308, C-1400, Austin, TX 78712; , .), AO(Department of Physics, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801; .), AP(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), AQ(Optical and Infrared Astronomy Division, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , , , , , .), AR(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), AS(Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan; , , .; Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; , .), AT(Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan; , , .; Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; , .), AU(Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan; , , .; Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; , .), AV(Department of Physics, Aoyama Gakuin University, 6-16-1 Chitosedai, Sagamihara, Kanagawa 229-8558, Japan; .), AW(Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; , .), AX(Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; , .), AY(Optical and Infrared Astronomy Division, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , , , , , .), AZ(Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 .), BA(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), BB(Optical and Infrared Astronomy Division, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , , , , , .; Astronomical Data Analysis Center, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; .), BC(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), BD(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), BE(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720; , , , , , , , , .), BF(Astronomical Data Analysis Center, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; .), BG(Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan; .), BH(Public Relations Center, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; .; Optical and Infrared Astronomy Division, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , , , , , .), BI(Optical and Infrared Astronomy Division, NAOJ, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , , , , , .)
Publication:
The Astrophysical Journal, Volume 593, Issue 1, pp. L19-L22. (ApJ Homepage)
Publication Date:
08/2003
Origin:
UCP
ApJ Keywords:
Gamma Rays: Bursts, Nuclear Reactions, Nucleosynthesis, Abundances, Polarization, Stars: Supernovae: General, Stars: Supernovae: Individual: Alphanumeric: SN 2003dh
DOI:
10.1086/378148
Bibliographic Code:
2003ApJ...593L..19K

Abstract

Spectroscopic and spectropolarimetric observations of SN 2003dh/GRB 030329 obtained in 2003 May using the Subaru 8.2 m Telescope are presented. The properties of the supernova (SN) are investigated through a comparison with spectra of the Type Ic hypernovae SN 1997ef and SN 1998bw (hypernovae being a tentatively defined class of SNe with very broad absorption features: these features suggest a large velocity of the ejected material and possibly a large explosion kinetic energy). Comparison with spectra of other hypernovae shows that the spectrum of SN 2003dh obtained on 2003 May 8 and 9, i.e., 34-35 rest-frame days after the gamma-ray burst (GRB; for z=0.1685), are similar to those of SN 1997ef obtained ~34-42 days after the fiducial time of explosion of that SN. The match with SN 1998bw spectra is not as good (at rest 7300-8000 Å), but again spectra obtained ~33-43 days after GRB 980425 are preferred. This indicates that the SN may have intermediate properties between SNe 1997ef and 1998bw. On the basis of the analogy with the other hypernovae, the time of explosion of SN 2003dh is then constrained to be between -8 and +2 days of the GRB. The Si and O P Cygni lines of SN 2003dh seem comparable to those of SN 1997ef, which suggests that the ejected mass in SN 2003dh may match that in SN 1997ef. Polarization was marginally detected at optical wavelengths. This is consistent with measurements of the late afterglow, implying that it originated mostly in the interstellar medium of the host galaxy.

Based on data obtained at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan (NAOJ).



Title:
On the Origin of Lyα Blobs at High Redshift: Kinematic Evidence of a Hyperwind Galaxy at z = 3.1
Authors:
Ohyama, Youichi; Taniguchi, Yoshiaki; Kawabata, Koji S.; Shioya, Yasuhiro; Murayama, Takashi; Nagao, Tohru; Takata, Tadafumi; Iye, Masanori; Yoshida, Michitoshi
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, Hilo, HI 96720.), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AC(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AD(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AE(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AF(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AG(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, Hilo, HI 96720.), AH(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomy, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AI(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan.)
Publication:
The Astrophysical Journal, Volume 591, Issue 1, pp. L9-L12. (ApJ Homepage)
Publication Date:
07/2003
Origin:
UCP
ApJ Keywords:
Galaxies: Evolution, Galaxies: Formation, Galaxies: Starburst
DOI:
10.1086/376959
Bibliographic Code:
2003ApJ...591L...9O

Abstract

We present deep optical spectroscopy of an extended Lyα emission-line blob located in an overdense region at redshift z~3.1 (``blob 1'' of Steidel et al.). The origin of such Lyα blobs has been debated for some time; two of the most plausible models are (1) that it comes from a dust-enshrouded, extreme starburst galaxy with a large-scale galactic outflow (superwind/hyperwind) or (2) that it is the cooling radiation of protogalaxies in dark matter halos. Examination of the kinematic properties of the Lyα emission-line gas should allow us to determine its nature. With this motivation, we performed optical spectroscopy on blob 1 using the Subaru Telescope and found that its kinematic properties can be well explained in terms of superwind activity.

Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.



Title:
Dusty ERO Search behind Two Massive Clusters
Authors:
Takata, Tadafumi; Kashikawa, Nobunari; Nakanishi, Kouichiro; Aoki, Kentaro; Asai, Ryo; Ebizuka, Noboru; Inata, Motoko; Iye, Masanori; Kawabata, Koji S.; Kosugi, George; Ohyama, Youichi; Okita, Kiichi; Sasaki, Toshiyuki; Saito, Yoshihiko; Sekiguchi, Kazuhiro; Shimizu, Yasuhiro; Taguchi, Hiroko; Yoshida, Michitoshi
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan), AB(Opt/IR Astronomy Division, National Astronomical Observatory), AC(Nobeyama Radio Observatory, National Astronomical Observatory), AD(Subaru Telescope, National Astronomical Observatory of Japan), AE(Opt/IR Astronomy Division, National Astronomical Observatory), AF(RIKEN, The Institute of Physical and Chemical Research), AG(Okayama Astrophysical Observatory , National Astronomical Observatory), AH(Opt/IR Astronomy Division, National Astronomical Observatory), AI(Opt/IR Astronomy Division, National Astronomical Observatory), AJ(Subaru Telescope, National Astronomical Observatory of Japan), AK(Subaru Telescope, National Astronomical Observatory of Japan), AL(Okayama Astrophysical Observatory , National Astronomical Observatory), AM(Subaru Telescope, National Astronomical Observatory of Japan), AN(Opt/IR Astronomy Division, National Astronomical Observatory), AO(Subaru Telescope, National Ast! ronomical Observatory of Japan), AP(Okayama Astrophysical Observatory , National Astronomical Observatory), AQ(Opt/IR Astronomy Division, National Astronomical Observatory), AR(Okayama Astrophysical Observatory , National Astronomical Observat ory)
Publication:
Publications of the Astronomical Society of Japan, Vol.55, No.4, pp. 789-800 (PASJ Homepage)
Publication Date:
06/2003
Origin:
PASJ
Keywords:
galaxies: clusters: individual (MS 0451.6‑0305, MS 0440.5+0204) -- galaxies: evolution -- galaxies: high-redshift -- galaxies: individual (SMM J04542‑0301, SMM J04541‑0302)
Bibliographic Code:
2003PASJ...55..789T

Abstract

We performed deep K'-band imaging observations of 2 massive clusters, MS 0451.6 - 0305 at z = 0.55 and MS 0440.5 + 0204 at z = 0.19, for searching counterparts of the faint sub-mm sources behind these clusters, which would provide one of the deepest extremely red object (ERO) samples. Comparing our near-infrared images with optical images taken by the Hubble Space Telescope and by the Subaru Telescope, we identified 13 EROs in these fields. The sky distributions of EROs are consistent with the previous results, that there is a sign of strong clustering among detected EROs. Also, the surface density with corrected lensing amplification factors in both clusters are in good agreement with that derived from previous surveys. We found 7 EROs and 3 additional very red objects in a small area (˜ 0.6 arcmin2) of the MS 0451.6 - 0305 field around an extended SCUBA source. Many of their optical and near-infrared colors are consistent with dusty st ar-forming galaxies at high redshifts ( z ˜ 1.0 - 4.0 ), and they may be constituting a cluster of dusty starburst galaxies and/or lensed star-forming galaxies at high redshift. Their red J-K' colors and faint optical magnitudes suggest they are relatively old massive stellar systems with ages (> 300 mega years) suffering from dust obscuration. We also found a surface-density enhancement of EROs around the SCUBA source in the MS 0440.5 + 0204 field.


Title:
The Discovery of Two Lyman α Emitters beyond Redshift 6 in the Subaru Deep Field
Authors:
Kodaira, Keiichi; Taniguchi, Yoshiaki; Kashikawa, Nobunari; Kaifu, Norio; Ando, Hiroyasu; Karoji, Hiroshi; Ajiki, Masaru; Akiyama, Masayuki; Aoki, Kentaro; Doi, Mamoru; Fujita, Shinobu S.; Furusawa, Hisanori; Hayashino, Tomoki; Imanishi, Masatoshi; Iwamuro, Fumihide; Iye, Masanori; Kawabata, Koji S.; Kobayashi, Naoto; Kodama, Tadayuki; Komiyama, Yutaka; Kosugi, George; Matsuda, Yuichi; Miyazaki, Satoshi; Mizumoto, Yoshihiko; Motohara, Kentaro; Murayama, Takashi; Nagao, Tohru; Nariai, Kyoji; Ohta, Kouji; Ohyama, Youichi; Okamura, Sadanori; Ouchi, Masami; Sasaki, Toshiyuki; Sekiguchi, Kazuhiro; Shimasaku, Kazuhiro; Shioya, Yasunori; Takata, Tadafumi; Tamura, Hajime; Terada, Hiroshi; Umemura, Masayuki; Usuda, Tomonori; Yagi, Masafumi; Yamada, Toru; Yasuda, Naoki; Yoshida, Michitoshi
Affiliation:
AA(The Graduate University for Advanced Studies, SOKENDAI), AB(Astronomical Institute, Graduate School of Science, Tohoku University), AC(National Astronomical Observatory of Japan), AD(National Astronomical Observatory of Japan), AE(National Astronomical Observatory of Japan), AF(Subaru Telescope, National Astronomical Observatory of Japan), AG(Astronomical Institute, Graduate School of Science, Tohoku University), AH(Subaru Telescope, National Astronomical Observatory of Japan), AI(Subaru Telescope, National Astronomical Observatory of Japan), AJ(Institute of Astronomy, Graduate School of Science, The University of Tokyo), AK(Astronomical Institute, Graduate School of Science, Tohoku University), AL(Subaru Telescope, National Astronomical Observatory of Japan), AM(Research Center for Neutrino Science, Graduate School of Science, Tohoku University), AN(National Astronomical Observatory of Japan), AO(Dept. of Astronomy, Graduate School of Science, Kyoto University), AP(National Astronomi cal Observatory of Japan), AQ(National Astronomical Observatory of Japan), AR(Subaru Telescope, National Astronomical Observatory of Japan), AS(National Astronomical Observatory of Japan), AT(Subaru Telescope, National Astronomical Observatory of Japan), AU(Subaru Telescope, National Astronomical Observatory of Japan), AV(Research Center for Neutrino Science, Graduate School of Science, Tohoku University), AW(Subaru Telescope, National Astronomical Observatory of Japan), AX(National Astronomical Observatory of Japan), AY(Institute of Astronomy, Graduate School of Science, The University of Tokyo), AZ(Astronomical Institute, Graduate School of Science, Tohoku University), BA(Astronomical Institute, Graduate School of Science, Tohoku University), BB(Dept. of Physics, Meisei University), BC(Dept. of Astronomy, Graduate School of Science, Kyoto University), BD(Subaru Telescope, National Astronomical Observatory of Japan), BE(Dept. of Astronomy, Graduate School of Science, The University of Tokyo/Research Center for the Early Universe, Graduate School of Science, The University of Tokyo), BF(Dept. of Astronomy, Graduate School of Science, The University of Tokyo), BG(Subaru Telescope, National Astronomical Observatory of Japan), BH(Subaru Telescope, National Astronomical Observatory of Japan), BI(Dept. of Astronomy, Graduate School of Science, The University of Tokyo), BJ(Astronomical Institute, Graduate School of Science, Tohoku University), BK(Subaru Telescope, Nation al Astronomical Observatory of Japan), BL(Research Center for Neutrino Science, Graduate School of Science, Tohoku University), BM(Subaru Telescope, National Astronomical Observatory of Japan), BN(Center for Computational Physics, University of Tsukuba), BO(Subaru Telescope, National Astronomical Observatory of Japan), BP(National Astronomical Observatory of Japan), BQ(National Astronomical Observatory of Japan), BR(National Astronomical Observatory of Japan), BS(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan)
Publication:
Publications of the Astronomical Society of Japan, Vol.55, No.2, pp. L17-L21 (PASJ Homepage)
Publication Date:
04/2003
Origin:
PASJ
Keywords:
cosmology: observations, early universe, galaxies: evolution, galaxies: formation, galaxies: starburst
Bibliographic Code:
2003PASJ...55L..17K

Abstract

We performed a deep optical imaging survey using a narrow-band filter (NB921) centered at λ = 9196 Å together with i' and z'broadband filters covering an 814 arcmin2area of the Subaru Deep Field. We obtained a sample of 73 strongNB921-excess objects based on the following two color criteria: z - NB921 > 1 andi' - z'> 1.3.We then obtained optical spectroscopy of nine objects in our NB921-excess sample, and identified at least two Lyα emitters atz=6.541 ± 0.002 andz=6.578 ± 0.002, each of which shows the characteristic sharp cutofftogether with continuum depression at wavelengths shortward of the line peak.The latter object is more distant than HCM-6A at z = 6.56, which is the most distant known object that has been found so far.These new data allow us to estimate the first meaningful lower limit of the star-formation rate density beyond redshift 6; ρSFR ˜ 5.2 × 10-4Mȯyr-1 Mpc-3.Since it is expected that the actual density is several times higher than this value, our new observation reveals that a moderately high level of star formation activity already occurred at z ˜ 6.6.


Title:
Subaru Deep Survey. IV. Discovery of a Large-Scale Structure at Redshift ~=5
Authors:
Shimasaku, K.; Ouchi, M.; Okamura, S.; Kashikawa, N.; Doi, M.; Furusawa, H.; Hamabe, M.; Hayashino, T.; Kawabata, K.; Kimura, M.; Kodaira, K.; Komiyama, Y.; Matsuda, Y.; Miyazaki, M.; Miyazaki, S.; Nakata, F.; Ohta, K.; Ohyama, Y.; Sekiguchi, M.; Shioya, Y.; Tamura, H.; Taniguchi, Y.; Yagi, M.; Yamada, T.; Yasuda, N.
Affiliation:
AA(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan; .; Research Center for the Early Universe, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AB(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan; .), AC(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan; .; Research Center for the Early Universe, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AD(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan.), AE(Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-0015, Japan.), AF(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AG(Department of Mathematical and Physical Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan.), AH(Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AI(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan.), AJ(Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan.), AK(Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan.), AL(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AM(Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AN(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan; .), AO(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AP(Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK.), AQ(Department of Astronomy, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.), AR(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AS(Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan.), AT(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AU(Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AV(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AW(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan.), AX(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan.), AY(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan.)
Publication:
The Astrophysical Journal, Volume 586, Issue 2, pp. L111-L114. (ApJ Homepage)
Publication Date:
04/2003
Origin:
UCP
ApJ Keywords:
Cosmology: Observations, Cosmology: Early Universe, Galaxies: Evolution, Galaxies: High-Redshift, Galaxies: Photometry, Cosmology: Large-Scale Structure of Universe
DOI:
10.1086/374880
Bibliographic Code:
2003ApJ...586L.111S

Abstract

We report the discovery of a large-scale structure of Lyα emitters (LAEs) at z=4.86 based on wide-field imaging with the prime-focus camera (Suprime-Cam) on the Subaru Telescope. We observed a 25'×45' area of the Subaru Deep Field in a narrow band (NB711, λc=7126 Å and FWHM=73 Å) together with R and i'. We isolate from these data 43 LAE candidates down to NB711=25.5 mag using color criteria. Follow-up spectroscopy of five candidates suggests the contamination by low-z objects to be ~20%. We find that the LAE candidates are clustered in an elongated region on the sky of 20 Mpc in width and 50 Mpc in length at z=4.86, which is comparable in size to present-day large-scale structures (we adopt H0=70 km s-1 Mpc-1, Ω0=0.3, and λ0=0.7). This elongated region includes a circular region of 12 Mpc radius of higher surface overdensity (δΣ=2), which may be the progenitor of a cluster of galaxies. Assuming this circular region to be a sphere with a spatial overdensity of 2, we compare our observation with predictions by cold dark matter models. We find that an Ω0=0.3 flat model with σ8=0.9 predicts the number of such spheres consistent with the observed number (one sphere in our survey volume) if the bias parameter of LAEs is b~=6. This value suggests that the typical mass of dark halos hosting LAEs at z~=5 is of the order of 1012 Msolar. Such a large mass poses an interesting question about the nature of LAEs.

Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.



Title:
Subaru Deep Survey. III. Evolution of Rest-Frame Luminosity Functions Based on the Photometric Redshifts for a K'-Band-Selected Galaxy Sample
Authors:
Kashikawa, Nobunari; Takata, Tadafumi; Ohyama, Youichi; Yoshida, Michitoshi; Maihara, Toshinori; Iwamuro, Fumihide; Motohara, Kentaro; Totani, Tomonori; Nagashima, Masahiro; Shimasaku, Kazuhiro; Furusawa, Hisanori; Ouchi, Masami; Yagi, Masafumi; Okamura, Sadanori; Iye, Masanori; Sasaki, Toshiyuki; Kosugi, George; Aoki, Kentaro; Nakata, Fumiaki
Affiliation:
AA(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan; .; Department of Astronomy, School of Science, Graduate University for Advanced Studies, Mitaka, Tokyo, 181-8588, Japan.), AB(Subaru Telescope, National Astronomical Observatory, 650 North A`ohoku Place, Hilo, HI 96720.), AC(Subaru Telescope, National Astronomical Observatory, 650 North A`ohoku Place, Hilo, HI 96720.), AD(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan; .; Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232, Japan.), AE(Department of Astronomy, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan.), AF(Department of Astronomy, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan.), AG(Institute of Astronomy, University of Tokyo, Mitaka, Tokyo 181-8588, Japan.), AH(Princeton University Observatory, Peyton Hall, Princeton, NJ 08544.; Theoretical Astrophysics Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AI(Theoretical Astrophysics Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AJ(Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033, Japan.; Research Center for the Early Universe, University of Tokyo, Hongo, Tokyo 113-0033, Japan.), AK(Subaru Telescope, National Astronomical Observatory, 650 North A`ohoku Place, Hilo, HI 96720.), AL(Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033, Japan.), AM(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan; .), AN(Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033, Japan.; Research Center for the Early Universe, University of Tokyo, Hongo, Tokyo 113-0033, Japan.), AO(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan; .; Department of Astronomy, School of Science, Graduate University for Advanced Studies, Mitaka, Tokyo, 181-8588, Japan.), AP(Subaru Telescope, National Astronomical Observatory, 650 North A`ohoku Place, Hilo, HI 96720.), AQ(Subaru Telescope, National Astronomical Observatory, 650 North A`ohoku Place, Hilo, HI 96720.), AR(Subaru Telescope, National Astronomical Observatory, 650 North A`ohoku Place, Hilo, HI 96720.), AS(Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033, Japan.)
Publication:
The Astronomical Journal, Volume 125, Issue 1, pp. 53-65. (AJ Homepage)
Publication Date:
01/2003
Origin:
UCP
AJ Keywords:
Cosmology: Observations, Galaxies: Evolution, Galaxies: Luminosity Function, Mass Function
DOI:
10.1086/344807
Bibliographic Code:
2003AJ....125...53K

Abstract

We have constructed a very deep K'-selected multicolor BVRIz'JK' sample of 439 field galaxies. Based on this multicolor data, a photometric redshift for each sample galaxy was estimated. The overall redshift distribution N(z) for the K'<=21.0 sample is consistent with previous observations, and for the first time we derive N(z) down to K'=24.0. After taking account of the dust extinction and selection effects of the sample, the observed N(z) distribution is well described with the pure luminosity evolution (PLE) model, while the hierarchical galaxy formation model shows an apparent deficiency of galaxies especially at z>~2. The photometric redshift and the best-fit spectral energy distribution model evaluations allow the derivation of the rest-frame K', B, and UV (2000 Å) band luminosity functions and their evolutions. The rest K'-band luminosity function shows almost no evolution up to z=3, while the rest B luminosity function shows mild luminosity evolution, and the rest UV luminosity function shows strong luminosity evolution. These findings seem to be qualitatively in favor of the PLE model. No evolution in the rest K'-band luminosity function can also be consistent with the hierarchical galaxy formation model if M/LK decreases with redshift, that is, if the number density of K'-band luminosity-selected galaxies does not significantly change with redshift while the number density of stellar mass-selected galaxies decreases with look-back time. This trend corresponds to the evolution of the rest UV (2000 Å)-K' color, which gets bluer with increasing redshift. We also found that more massive galaxies are redder in this rest-frame color in every epoch. The rest UV luminosity function of our K'-selected galaxies shows a much shallower faint-end slope at z=3 than that of previous estimations for rest UV-selected Lyman break galaxies. As a consequence, the contribution to the global star formation rate of our K'-selected galaxies is about 42% of that derived from the integration of the luminosity function of Lyman break galaxies at z=3. This result suggests that a large fraction of the star formation rate density at z>1.5 comes from the contribution from a faint (M2000>-20) blue galaxy population at high redshift that has not yet obviously been identified. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.


Title:
SDSSp J104433.04?012502.2 at z=5.74 is Gravitationally Magnified by an Intervening Galaxy
Authors:
Shioya, Yasuhiro; Taniguchi, Yoshiaki; Murayama, Takashi; Ajiki, Masaru; Nagao, Tohru; Fujita, Shinobu S.; Kakazu, Yuko; Komiyama, Yutaka; Okamura, Sadanori; Oyabu, Shinki; Kawara, Kimiaki; Ohyama, Youichi; Kawabata, Koji S.; Ando, Hiroyasu; Nishimura, Tetsuo; Hayashi, Masahiko; Ogasawara, Ryusuke; Ichikawa, Shin-Ichi
Affiliation:
AA(Astronomical Institute, Graduate School of Science, Tohoku University), AB(Astronomical Institute, Graduate School of Science, Tohoku University), AC(Astronomical Institute, Graduate School of Science, Tohoku University), AD(Astronomical Institute, Graduate School of Science, Tohoku University), AE(Astronomical Institute, Graduate School of Science, Tohoku University), AF(Astronomical Institute, Graduate School of Science, Tohoku University), AG(Institute for Astronomy, University of Hawaii), AH(Subaru Telescope, National Astronomical Observatory of Japan), AI(Dept. of Astronomy, Graduate School of Science, The University of Tokyo/Research Center for the Early Universe, School of Science, The University of Tokyo), AJ(Institute of Astronomy, Graduate School of Science, The University of Tokyo), AK(Institute of Astronomy, Graduate School of Science, The University of Tokyo), AL(Subaru Telescope, National Astronomical Observatory of Japan), AM(Na tional Astronomical Observatory), AN(Subaru Telescope, National Astronomical Observatory of Japan), AO(Subaru Telescope, National Astronomical Observatory of Japan), AP(Subaru Telescope, National Astronomical Observatory of Japan), AQ(Subaru Telescope, National Astronomical Observatory of Japan), AR(National Astronomical Observatory)
Publication:
Publications of the Astronomical Society of Japan, Vol.54, No.6, pp.975-979 (PASJ Homepage)
Publication Date:
12/2002
Origin:
PASJ
Keywords:
galaxies: high-redshift, galaxies: quasars: individual (SDSSp J104433.04012502.2), gravitational lensing
Bibliographic Code:
2002PASJ...54..975S

Abstract

During the course of our optical deep survey program on Lα emitters at z ≈ 5.7 in the sky area surrounding the quasar SDSSp J104433.04 012502.2 at z = 5.74, we found that a faint galaxy with mB(AB) ≈ 25 is located at 1."9 southwest of the quasar. Its broad-band color properties from B to z' suggest that the galaxy is located at a redshift of z ˜ 1.5 2.5. This is consistent with no strong emission line in our optical spectroscopy. Since the counter-image of the quasar cannot be seen in our deep optical images, the magnification factor seems not to be very high. Our modest estimate is that this quasar is gravitationally magnified by a factor of 2.


Title:
Decomposition of the Superwind in M 82
Authors:
Ohyama, Youichi; Taniguchi, Yoshiaki; Iye, Masanori; Yoshida, Michitoshi; Sekiguchi, Kazuhiro; Takata, Tadafumi; Saito, Yoshihiko; Kawabata, Koji S.; Kashikawa, Nobunari; Aoki, Kentaro; Sasaki, Toshiyuki; Kosugi, George; Okita, Kiichi; Shimizu, Yasuhiro; Inata, Motoko; Ebizuka, Noboru; Ozawa, Tomohiko; Yadoumaru, Yasushi; Taguchi, Hiroko; Asai, Ryo
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan), AB(Astronomical Institute, Graduate School of Science, Tohoku University), AC(National Astronomical Observatory of Japan/Dept. of Astronomy, Graduate University for A dvanced Studies), AD(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan), AE(Subaru Telescope, National Astronomical Observatory of Japan), AF(Subaru Telescope, National Astronomical Observatory of Japan), AG(National Astronomical Observatory of Japan), AH(National Astronomical Observatory of Japan), AI(National Astronomical Observatory of Japan), AJ(Institute of Astronomy, Graduate School of Science, The University of Tokyo), AK(Subaru Telescope, National Astronomical Observatory of Japan), AL(Subaru Telescope, National Astronomical Observatory of Japan), AM(Subaru Telescope, National Astronomical Observatory of Japan), AN(Okayama Astrophysical Observatory, National Astronomical Observatory of Japan), AO(National Astronomical Obse rvatory of Japan), AP(Cosmic Radiation Laboratory, Institute of Physical and Chemical Researc, RIKEN), AQ(Misato Observatory), AR(Misato Observatory), AS(Dept. of Astronomy and Earth Sciences, Tokyo Gakugei University), AT(Systems Engineering Consultants Co., Ltd.)
Publication:
Publications of the Astronomical Society of Japan, Vol.54, No.6, pp.891-898 (PASJ Homepage)
Publication Date:
12/2002
Origin:
PASJ
Keywords:
galaxies: individual (M 82), galaxies: intergalactic medium, galaxies: starburst, medium, shock waves
Bibliographic Code:
2002PASJ...54..891O

Abstract

We present new optical images (B, V, Hα) of the archetypical starburst/superwind galaxy M 82 obtained with the 8.2m Subaru Telescope to reveal new detailed structures of the superwind-driven nebula and the high-latitude dark lanes. The emission-line nebula is decomposed into (1) a ridge-dominated component comprising numerous filament/loop sub-structures whose overall morphology appears as a pair of narrow cylinders, and (2) a diffuse component extended over much wider opening angle from the nucleus. We suggest that these two components have different origins. The ridge-dominated component appears as a pair of cylinders rather than a pair of cones. Since this morphological property is similar to that of hot plasma probed by soft X-ray, this component seems to surround the hot plasma. On the other hand, the diffuse component may arise from dust grains which scatter stellar light from the galaxy. Since inner region of this component is seen over the promi nent ``X''-shaped dark lanes streaming out from the nuclear region and they can be reproduced as a conical distribution of dust grains, there seems to be a dusty cold outflow as well as the hot one probed by soft X-ray and shock-excited optical emission lines. If this is the case, the presence of such high-latitude dust grains implies that neutral gaseous matter is also blown out during the course of the superwind activity.


Title:
FOCAS: The Faint Object Camera and Spectrograph for the Subaru Telescope
Authors:
Kashikawa, Nobunari; Aoki, Kentaro; Asai, Ryo; Ebizuka, Noboru; Inata, Motoko; Iye, Masanori; Kawabata, Koji S.; Kosugi, George; Ohyama, Youichi; Okita, Kiichi; Ozawa, Tomohiko; Saito, Yoshihiko; Sasaki, Toshiyuki; Sekiguchi, Kazuhiro; Shimizu, Yasuhiro; Taguchi, Hiroko; Takata, Tadafumi; Yadoumaru, Yasushi; Yoshida, Michitoshi
Affiliation:
AA(Optical and Infrared Astronomy Division, National Astronomical Observatory/Dept. of Astronomy, School of Science, Graduate University for Advanced Studies), AB(Subaru Telescope, National Astronomical Observatory), AC(Dept. of Astronomy, School of Science, The University of Tokyo), AD(Communications Research Laboratory), AE(Optical and Infrared Astronomy Division, National Astronomical Observatory), AF(Optical and Infrared Astronomy Division, National Astronomical Observatory/Dept. of Astronomy, School of Science, Graduate University for Advanced Studies), AG(Optical and Infrared Astronomy Division, National Astronomical Observatory), AH(Subaru Telescope, National Astronomical Observatory), AI(Subaru Telescope, National Astronomical Observatory), AJ(Optical and Infrared Astronomy Division, National Astronomical Observatory), AK(Misato Observatory), AL(Dept. of Astronomy, School of Science, The University of Tokyo), AM(Subaru Telescope, Nationa l Astronomical Observatory), AN(Subaru Telescope, National Astronomical Observatory), AO(Okayama Astrophysical Observatory, National Astronomical Observatory), AP(Dept. of Astronomy and Earth Sciences, Tokyo Gakugei University), AQ(Subaru Telescope, National Astronomical Observatory), AR(Misato Observatory), AS(Optical and Infrared Astronomy Division, National Astronomical Observatory)
Publication:
Publications of the Astronomical Society of Japan, Vol.54, No.6, pp.819-832 (PASJ Homepage)
Publication Date:
12/2002
Origin:
PASJ
Keywords:
instrumentation: spectrographs
Bibliographic Code:
2002PASJ...54..819K

Abstract

The Faint Object Camera and Spectrograph (FOCAS) is a Cassegrain optical instrument for the Subaru Telescope. Its capabilities include 6'φ FOV direct imaging, low-resolution spectroscopy (R=250 - 2000 with 0".4 slitwidth), multi-slit spectroscopy and polarimetry. We describe the overall design of FOCAS, its observing functions, and the performance verification procedures that have been carried out.


Title:
Optical Spectropolarimetry of SN 2002ap: A High-Velocity Asymmetric Explosion
Authors:
Kawabata, K. S.; Jeffery, D. J.; Iye, M.; Ohyama, Y.; Kosugi, G.; Kashikawa, N.; Ebizuka, N.; Sasaki, T.; Sekiguchi, K.; Nomoto, K.; Mazzali, P.; Deng, J.; Maeda, K.; Umeda, H.; Aoki, K.; Saito, Y.; Takata, T.; Yoshida, M.; Asai, R.; Inata, M.; Okita, K.; Ota, K.; Ozawa, T.; Shimizu, Y.; Taguchi, H.; Yadoumaru, Y.; Misawa, T.; Nakata, F.; Yamada, T.; Tanaka, I.; Kodama, T.
Affiliation:
AA(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.; .), AB(Department of Physics, New Mexico Institute of Mining and Technology, Socorro, NM 87801.), AC(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomy, Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588, Japan.), AD(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720.), AE(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720.), AF(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.), AG(RIKEN, Wako, Saitama 351-0198, Japan.), AH(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720.), AI(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720.), AJ(Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.; Research Center for the Early Universe, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), AK(Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.; Research Center for the Early Universe, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.; Osservatorio Astronomico, Via Tiepolo 11, 34131 Trieste, Italy.), AL(Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.; Research Center for the Early Universe, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), AM(Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), AN(Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), AO(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720.), AP(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.), AQ(Subaru Telescope, NAOJ, 650 North A`ohoku Place, Hilo, HI 96720.), AR(Okayama Astrophysical Observatory, NAOJ, Asakuchi-gun, Okayama 719-0232, Japan.), AS(Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), AT(Okayama Astrophysical Observatory, NAOJ, Asakuchi-gun, Okayama 719-0232, Japan.), AU(Okayama Astrophysical Observatory, NAOJ, Asakuchi-gun, Okayama 719-0232, Japan.), AV(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), AW(Misato Observatory, Amakusa-gun, Wakayama 640-1366, Japan.), AX(Okayama Astrophysical Observatory, NAOJ, Asakuchi-gun, Okayama 719-0232, Japan.), AY(Department of Astronomy and Earth Science, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan.), AZ(Misato Observatory, Amakusa-gun, Wakayama 640-1366, Japan.), BA(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), BB(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.; Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.), BC(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.), BD(Optical and Infrared Astronomy Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.), BE(Theory Division, NAOJ, Mitaka, Tokyo 181-8588, Japan.)
Publication:
The Astrophysical Journal, Volume 580, Issue 1, pp. L39-L42. (ApJ Homepage)
Publication Date:
11/2002
Origin:
UCP
ApJ Keywords:
Polarization, Stars: Supernovae: Individual: Alphanumeric: SN 2002ap
DOI:
10.1086/345545
Bibliographic Code:
2002ApJ...580L..39K

Abstract

We present spectropolarimetry of the Type Ic supernova SN 2002ap and give a preliminary analysis: the data were taken at two epochs, close to and 1 month later than the visual maximum (2002 February 8). In addition, we present June 9 spectropolarimetry without analysis. The data show the development of linear polarization. Distinct polarization profiles were seen only in the O I λ7773 multiplet/Ca II IR triplet absorption trough at maximum light and in the O I λ7773 multiplet and Ca II IR triplet absorption troughs a month later, with the latter showing a peak polarization as high as ~2%. The intrinsic polarization shows three clear position angles: 80° for the February continuum, 120° for the February line feature, and 150° for the March data. We conclude that there are multiple asymmetric components in the ejecta. We suggest that the supernova has a bulk asymmetry with an axial ratio projected on the sky that is different from 1 by an order of 10%. Furthermore, we suggest very speculatively that a high-velocity ejecta component moving faster than ~0.115c (e.g., a jet) contributes to polarization in the February epoch. Based on data obtained at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan (NAOJ).


Title:
A New High-Redshift Lyα Emitter: Possible Superwind Galaxy at z=5.69
Authors:
Ajiki, Masaru; Taniguchi, Yoshiaki; Murayama, Takashi; Nagao, Tohru; Veilleux, Sylvain; Shioya, Yasuhiro; Fujita, Shinobu S.; Kakazu, Yuko; Komiyama, Yutaka; Okamura, Sadanori; Sanders, David B.; Oyabu, Shinki; Kawara, Kimiaki; Ohyama, Youichi; Iye, Masanori; Kashikawa, Nobunari; Yoshida, Michitoshi; Sasaki, Toshiyuki; Kosugi, George; Aoki, Kentaro; Takata, Tadafumi; Saito, Yoshihiko; Kawabata, Koji S.; Sekiguchi, Kazuhiro; Okita, Kiichi; Shimizu, Yasuhiro; Inata, Motoko; Ebizuka, Noboru; Ozawa, Tomohiko; Yadoumaru, Yasushi; Taguchi, Hiroko; Ando, Hiroyasu; Nishimura, Tetsuo; Hayashi, Masahiko; Ogasawara, Ryusuke; Ichikawa, Shin-ichi
Affiliation:
AA(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan; .), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan; .), AC(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan; .), AD(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan; .), AE(Department of Astronomy, University of Maryland, College Park, MD 20742-2421.), AF(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan; .), AG(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan; .), AH(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822.), AI(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), AJ(Department of Astronomy, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.; Research Center for the Early Universe, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AK(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822.), AL(Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan.), AM(Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan.), AN(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), AO(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AP(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AQ(Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan.), AR(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), AS(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), AT(Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan.), AU(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), AV(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AW(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AX(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), AY(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), AZ(Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan.), BA(Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan.), BB(Communications Research Laboratory, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan.), BC(Misato Observatory, 180 Matsugamine, Misato-cho, Amakusa-gun, Wakayama 640-1366, Japan.), BD(Misato Observatory, 180 Matsugamine, Misato-cho, Amakusa-gun, Wakayama 640-1366, Japan.), BE(Department of Astronomy and Earth Sciences, Tokyo Gakugei University, 4-1-1 Nukui-Kitamachi, Koganei, Tokyo 184-8501, Japan.), BF(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), BG(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), BH(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), BI(Subaru Telescope, National Astronomical Observatory, 650 North A'ohoku Place, Hilo, HI 96720.), BJ(National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.)
Publication:
The Astrophysical Journal, Volume 576, Issue 1, pp. L25-L28. (ApJ Homepage)
Publication Date:
09/2002
Origin:
UCP
ApJ Keywords:
Galaxies: Formation, galaxies: individual (LAE J1044-0130), Galaxies: Starburst
DOI:
10.1086/343026
Bibliographic Code:
2002ApJ...576L..25A

Abstract

During the course of our deep optical imaging survey for Lyα emitters at z~5.7 in the field around the z=5.74 quasar SDSSp J104433.04-012502.2, we found a candidate strong emission line source. Follow-up optical spectroscopy shows that the emission-line profile of this object is asymmetric, showing excess red wing emission. These properties are consistent with an identification of Lyα emission at a redshift of z=5.687+/-0.002. The observed broad line width (ΔvFWHM~=340 km s-1) and excess red wing emission also suggest that this object hosts a galactic superwind. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan, and at the W. M. Keck Observatory.


Title:
Subaru Spectroscopy of the Gravitational Lens HST 14176+5226: Implications for a Large Cosmological Constant
Authors:
Ohyama, Youichi; Hamana, Takashi; Kashikawa, Nobunari; Chiba, Masashi; Futamase, Toshifumi; Iye, Masanori; Kawabata, Koji S.; Aoki, Kentaro; Sasaki, Toshiyuki; Kosugi, George; Takata, Tadafumi
Affiliation:
AA(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720), AB(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan), AC(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan), AD(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan), AE(Astronomical Institute, Tohoku University, Sendai 980-8578, Japan), AF(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan), AG(National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan), AH(Institute of Astronomy, University of Tokyo, Mitaka, Tokyo 181-0015, Japan), AI(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720), AJ(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720), AK(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720)
Publication:
The Astronomical Journal, Volume 123, Issue 6, pp. 2903-2912. (AJ Homepage)
Publication Date:
06/2002
Origin:
UCP
AJ Keywords:
Cosmology: Observations, Cosmology: Gravitational Lensing, Galaxies: Quasars: Individual: Alphanumeric: HST 14176+5226
DOI:
10.1086/340565
Bibliographic Code:
2002AJ....123.2903O

Abstract

We present new optical spectroscopy of the lens elliptical galaxy in the Einstein Cross lens system HST 14176+5226, using the Faint Object Camera and Spectrograph of the Subaru Telescope. Our spectroscopic observations are aimed at measuring the stellar velocity dispersion of the lens galaxy, located at high redshift of zL=0.81, as an important component to lens models. We have measured this dispersion to be 230+/-14 km s-1 (1 σ) inside 0.35 effective radii of the lens, based on the comparison between the observed galaxy spectrum and spectral templates of three G-K giants by means of the Fourier cross-correlation method. To extract the significance of this information on the geometry of the universe, which also affects the lensing of the background image, we attempt to fit three different lens models to the available data of the lens system. Provided that the lens galaxy has structural and dynamical properties (i.e., its radial density profile, core radius, and velocity anisotropy) similar to those of local elliptical galaxies, we calculate the likelihood function for the simultaneous reproduction of both the observed image splitting and the newly measured velocity dispersion of the lens. Although the confidence interval depends rather sensitively on the adopted lens models or their parameters, our experiments suggest the greater likelihood for a larger cosmological constant ΩΛ: the formal 1 σ lower limit on ΩΛ in the flat universe ranges from 0.73 to 0.97, whereas the 2 σ lower limit is basically unavailable. This method for determining the world model is thus dependent on lens models but is insensitive to other unavoidable ambiguities, such as the dust absorption or the evolutionary effects of galaxies. Exploring spectroscopic observations of more lens galaxies at high redshift may minimize the model uncertainties and thus place a much tighter constraint on ΩΛ. Based on observations made with the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.


Title:
Discovery of a Very Extended Emission-Line Region around the Seyfert 2 Galaxy NGC 4388
Authors:
Yoshida, Michitoshi; Yagi, Masafumi; Okamura, Sadanori; Aoki, Kentaro; Ohyama, Youichi; Komiyama, Yutaka; Yasuda, Naoki; Iye, Masanori; Kashikawa, Nobunari; Doi, Mamoru; Furusawa, Hisanori; Hamabe, Masaru; Kimura, Masahiko; Miyazaki, Masayuki; Miyazaki, Satoshi; Nakata, Fumiaki; Ouchi, Masami; Sekiguchi, Maki; Shimasaku, Kazuhiro; Ohtani, Hiroshi
Affiliation:
AA(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.; Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232, Japan; .), AB(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AC(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan.; Research Center for the Early Universe, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AD(Astronomical Data Analysis Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.; Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-8588, Japan.), AE(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AF(Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720.), AG(Astronomical Data Analysis Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AH(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AI(Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AJ(Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-8588, Japan.), AK(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AL(Department of Mathematical and Physical Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo 112-8681, Japan.), AM(Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan.), AN(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AO(Advanced Technology Center, National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan.), AP(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AQ(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AR(Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan.), AS(Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan.), AT(Department of Astronomy, Faculty of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.)
Publication:
The Astrophysical Journal, Volume 567, Issue 1, pp. 118-129. (ApJ Homepage)
Publication Date:
03/2002
Origin:
UCP
ApJ Keywords:
Galaxies: Active, Galaxies: Halos, galaxies: individual (NGC 4388), Galaxies: Interactions, Galaxies: Seyfert, Galaxies: Intergalactic Medium
DOI:
10.1086/338353
Bibliographic Code:
2002ApJ...567..118Y

Abstract

We found a very large, ~35 kpc, emission-line region around the Seyfert type 2 galaxy NGC 4388, using deep narrowband imaging with the prime focus camera (Suprime-Cam) of the Subaru Telescope. This region consists of many faint gas clouds, or filaments, and extends northeastward from the galaxy. The typical Hα luminosity L(Hα) of the clouds is ~1037 ergs s-1, and the total L(Hα) of the region within 10 kpc of the nucleus is ~2×1038 ergs s-1, which corresponds to an ionized gas mass of ~105 Msolar. The map of the emission-line intensity ratio I([O III])/I(Hα) indicates that the inner (r<12 kpc) region of the very extended emission-line region (VEELR) may be excited by nuclear ionizing radiation. The excitation mechanism of the outer (r>12 kpc) region is unclear, but it is likely that the nuclear radiation is also a dominant source of its ionization. We discuss the origin of the ionized gas. Two plausible origins of the gas in the VEELR are (1) the tidal debris resulting from a past interaction with a gas-rich dwarf galaxy, i.e., a minor merger, and (2) the interstellar medium of NGC 4388, stripped by the ram pressure of the hot intracluster medium of the Virgo Cluster. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.


Title:
A Shock-induced Pair of Superbubbles in the High-Redshift Powerful Radio Galaxy MRC 0406-244
Authors:
Taniguchi, Yoshiaki; Ohyama, Youichi; Murayama, Takashi; Yoshida, Michitoshi; Kashikawa, Nobunari; Iye, Masanori; Aoki, Kentaro; Sasaki, Toshiyuki; Kosugi, George; Takata, Tadafumi; Saito, Yoshihiko; Kawabata, Koji S.; Sekiguchi, Kazuhiro; Okita, Kiichi; Shimizu, Yasuhiro; Inata, Motoko; Ebizuka, Noboru; Ozawa, Tomohiko; Yadomaru, Yasushi; Taguchi, Hiroko; Shioya, Yasuhiro; Nishiura, Shingo; Sudou, Hiroshi; Nagao, Tohru; Noda, Saeko; Koyama, Yohei; Kakazu, Yuko; Ajiki, Masaru; Fujita, Shinobu S.; Kobayashi, Rie R.
Affiliation:
AA(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AB(; Subaru Telescope Office, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AC(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AD(; Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan.), AE(; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AF(; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AG(; Japan Science and Technology Corporation, Tokyo 102-0081, Japan.), AH(; Subaru Telescope Office, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AI(; Subaru Telescope Office, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AJ(; Subaru Telescope Office, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AK(; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AL(; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AM(; Subaru Telescope Office, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AN(; Subaru Telescope Office, National Astronomical Observatory of Japan, 650 North A`ohoku Place, University Park, Hilo, HI 96720.), AO(; Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata-cho, Asakuchi-gun, Okayama 719-0232, Japan.), AP(; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.), AQ(; Communications Research Laboratory, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan.), AR(; Misato Observatory, 180 Matsugamine, Misato-cho, Amakusa-gun, Wakayama 640-1366, Japan.), AS(; Misato Observatory, 180 Matsugamine, Misato-cho, Amakusa-gun, Wakayama 640-1366, Japan.), AT(; Department of Astronomy and Earth Sciences, Tokyo Gakugei University, 4-1-1 Nukui-Kitamachi, Koganei, Tokyo 184-8501, Japan.), AU(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AV(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.; Kiso Observatory, University of Tokyo, Mitake, Kiso, Nagano 397-0101, Japan.), AW(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AX(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AY(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AZ(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), BA(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.; Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822.), BB(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), BC(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), BD(; Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.)
Publication:
The Astrophysical Journal, Volume 559, Issue 1, pp. L9-L12. (ApJ Homepage)
Publication Date:
09/2001
Origin:
UCP
ApJ Keywords:
Galaxies: Active, Galaxies: Individual: Alphanumeric: MRC 0406-244, Galaxies: Starburst, Radio Continuum: Galaxies
DOI:
10.1086/323652
Bibliographic Code:
2001ApJ...559L...9T

Abstract

We present new optical spectroscopy of the high-redshift powerful radio galaxy MRC 0406-244 at redshift of 2.429. We find that the two extensions toward the northwest and southeast probed in the rest-frame ultraviolet image are heated mainly by the nonthermal continuum of the active galactic nucleus. However, each extension shows a shell-like morphology, suggesting that they are a pair of superbubbles induced by the superwind activity rather than by the interaction between the radio jet and the ambient gas clouds. If this is the case, the intense starburst responsible for the formation of superbubbles could occur ~1×109 yr ago. On the other hand, the age of the radio jets may be on the order of ~106 yr, being much shorter than the starburst age. Therefore, the two events, i.e., the starburst and the radio jet activities, are independent phenomena. However, their directions of the expanding motions could be governed by the rotational motion of the gaseous component in the host galaxy. This idea appears to explain the alignment effect of MRC 0406-244. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.


Title:
Sub-Parsec-Scale Acceleration of the Radio Jet in the Powerful Radio Galaxy NGC 6251
Authors:
Sudou, Hiroshi; Taniguchi, Yoshiaki; Ohyama, Youichi; Kameno, Seiji; Sawada-Satoh, Satoko; Inoue, Makoto; Kaburaki, Osamu; Sasao, Tetsuo
Affiliation:
AA(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578; ), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578), AC(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578), AD(National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AE(National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AF(National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588), AG(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578), AH(National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588})
Publication:
Publ. of the Astronomical Society of Japan, v.52, p.989-L995. (PASJ Homepage)
Publication Date:
12/2000
Origin:
PASJ
Bibliographic Code:
2000PASJ...52..989S

Abstract

In order to investigate the genesis of a powerful radio jet, we have mapped the central 10 pc region of the nearby radio galaxy, NGC 6251, with a 0.2 pc resolution using Very Long Baseline Interferometer (VLBI) at two radio frequencies, 5 GHz and 15 GHz. We have found the sub-parsec-scale counterjet for the first time in this radio galaxy. This discovery allows us to investigate the jet acceleration based on the relativistic beaming model. } \kword{ galaxies: active -- galaxies: individual (NGC 6251) -- galaxies: jets -- galaxies: nuclei -- radio continuum: galaxies


Title:
A Dynamical Study of Galaxies in the Hickson Compact Groups
Authors:
Nishiura, Shingo; Shimada, Masashi; Ohyama, Youichi; Murayama, Takashi; Taniguchi, Yoshiaki
Affiliation:
AA(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.; Visiting astronomer, Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama, 719-0232 Japan), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.; Visiting astronomer, Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama, 719-0232 Japan.; Asahi Optical Co., Ltd., Optical Research Department, 2-36-9, Maeno-cho, Itabashi-ku, Tokyo, 174-8639, Japan.), AC(Visiting astronomer, Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama, 719-0232 Japan.; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan), AD(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.; Visiting astronomer, Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama, 719-0232 Japan), AE(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.; Visiting astronomer, Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama, 719-0232 Japan)
Publication:
The Astronomical Journal, Volume 120, Issue 4, pp. 1691-1712. (AJ Homepage)
Publication Date:
10/2000
Origin:
UCP
AJ Keywords:
Key word: Galaxies: Clusters: General, Galaxies: Interactions, Galaxies: Kinematics and Dynamics
DOI:
10.1086/301561
Bibliographic Code:
2000AJ....120.1691N

Abstract

To investigate dynamical properties of spiral galaxies in the Hickson compact groups (HCGs), we present rotation curves of 30 galaxies in 20 HCGs. We found as follows: (1) There is no significant relation between dynamical peculiarity and morphological peculiarity in HCG spiral galaxies. (2) There is no significant relation between the dynamical properties and the frequency distribution of nuclear activities in HCG spiral galaxies. (3) There are no significant correlations between the dynamical properties of HCG spiral galaxies and any group properties (i.e., size, velocity dispersion, galaxy number density, and crossing time). (4) Asymmetric and peculiar rotation curves are more frequently seen in the HCG spiral galaxies than in field spiral galaxies or in cluster ones. However, this tendency is more obviously seen in late-type HCG spiral galaxies. These results suggest that the dynamical properties of HCG spiral galaxies do not strongly correlate with the morphology, the nuclear activity, and the group properties. Our results also suggest that more frequent galaxy collisions occur in the HCGs than in the field and in the clusters.


Title:
Superwind-Driven Intense H_2 Emission in NGC 6240
Authors:
Ohyama, Youichi; Yoshida, Michitoshi; Takata, Tadafumi; Imanishi, Masatoshi; Usuda, Tomonori; Saito, Yoshihiko; Taguchi, Hiroko; Ebizuka, Noboru; Iwamuro, Fumihide; Motohara, Kentaro; Taguchi, Tomoyuki; Hata, Ryuji; Maihara, Toshinori; Iye, Masanori; Sasaki, Toshiyuki; Kosugi, George; Ogasawara, Ryusuke; Noumaru, Junichi; Mizumoto, Yoshihiko; Yagi, Masafumi; Chikada, Yoshihiro
Affiliation:
AA(Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588; ), AB(Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata-cho, Asakuchi-gun, Okayama 719-0232), AC(Subaru Telescope, National Astronomical Observatory of Japan, 650 A'ohoku Place, Hilo, HI 96720, USA), AD(Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588; Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA), AE(Subaru Telescope, National Astronomical Observatory of Japan, 650 A'ohoku Place, Hilo, HI 96720, USA), AF(Department of Astronomy, School of Science, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-0033), AG(Department of Astronomy and Earth Sciences, Tokyo Gakugei University, 4-1-1 Nukui-Kitamachi, Koganei, Tokyo 184-8501), AH(Communications Research Laboratory, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795), AI(Communications Research Laboratory, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795), AJ(Communications Research Laboratory, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795), AK(Communications Research Laboratory, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795), AL(Department of Physics, Faculty of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502), AM(Department of Astronomy, Faculty of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502), AN(Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-858), AO(Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-858), AP(Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-858), AQ(Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-858), AR(Subaru Telescope, National Astronomical Observatory of Japan, 650 A'ohoku Place, Hilo, HI 96720, USA), AS(Subaru Telescope, National Astronomical Observatory of Japan, 650 A'ohoku Place, Hilo, HI 96720, USA), AT(Subaru Telescope, National Astronomical Observatory of Japan, 650 A'ohoku Place, Hilo, HI 96720, USA), AU(Optical and Infrared Astronomy Division, National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588})
Publication:
Publ. of the Astronomical Society of Japan, v.52, p.563-576. (PASJ Homepage)
Publication Date:
08/2000
Origin:
PASJ
PASJ Keywords:
GALAXIES: INDIVIDUAL (NGC 6240), GALAXIES: INTERACTIONS, GALAXIES: INTERGALACTIC MEDIUM, INFRARED: GALAXIES, INFRARED: SPECTRA, SHOCK WAVES
Bibliographic Code:
2000PASJ...52..563O

Abstract

We have performed a long-slit K-band spectroscopic observation of the luminous infrared galaxy NGC 6240. Spatially extended H_2 emission is detected over 3.3 kpc around the two nuclei. The peak position of the H_2 v=1-0 S(1) emission is located at ~ 0.3''-0.'' north of the southern nucleus. Based on line-ratio analyses, we suggest that the excitation mechanism of H_2 is pure thermal at most positions. We find the following three velocity components in the H_2 emission around the southern nucleus and its south region: a blue-shifted component (\approx -250 km s^{-1} with respect to V_sys), which is recognized as a distinct C-shape distortion in the velocity field around the southern nucleus; a high-velocity blue-shifted ``wing'' component (\sim -1000 km s^{-1} with respect to V_sys); and a component indicating possible line splitting of \sim 500 km s^{-1}. We show that these kinematic properties can be reproduced by expanding motion of a shell-like structure around the southern nucleus. The offset peak position of the H_2 emission can be understood if we assume that the shell expanding to the north interacts with the extragalactic molecular gas which has been transferred during the merging of the two nuclei. At the interface the cloud-crushing mechanism may work efficiently, and shock-excited intense H_2 emission is thus expected there. With this mechanism, the H_2 luminosity can be explained without global shock driven by the collision of two nuclei. All of these findings lead us to propose a model in which most of the H_2$ emission is attributed to shock excitation driven by the superwind activity of the southern nucleus.


Title:
The Nuclear Activity of Galaxies in the Hickson Compact Groups
Authors:
Shimada, Masashi; Ohyama, Youichi; Nishiura, Shingo; Murayama, Takashi; Taniguchi, Yoshiaki
Affiliation:
AA(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578, Japan), AB(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578, Japan), AC(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578, Japan), AD(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578, Japan), AE(Astronomical Institute, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578, Japan)
Publication:
The Astronomical Journal, Volume 119, Issue 6, pp. 2664-2685. (AJ Homepage)
Publication Date:
06/2000
Origin:
UCP
AJ Keywords:
Galaxies: Nuclei, Galaxies: Seyfert, Galaxies: Starburst
DOI:
10.1086/301381
Bibliographic Code:
2000AJ....119.2664S

Abstract

In order to investigate the nuclear activity of galaxies residing in compact groups of galaxies, we present results of our optical spectroscopic program made at Okayama Astrophysical Observatory. We have performed optical spectroscopy of 69 galaxies belonging to 31 Hickson compact groups (HCGs) of galaxies. Among them, three galaxies have discordant redshifts and, moreover, spectral quality is too poor to classify another three galaxies. Therefore, we describe our results for the remaining 63 galaxies. Our main results are summarized as follows: (1) We have found in our sample 28 active galactic nuclei (AGNs), 16 H II nuclei, and 19 normal galaxies showing no emission line. We used this HCG sample for statistical analyses. (2) Comparing the frequency distributions of activity types between the HCGs and the field galaxies whose data are taken from Ho, Filippenko, & Sargent (382 field galaxies), we find that the frequency of H II nuclei in the HCGs is significantly less than that in the field. However, this difference may be due to selection bias to the effect that our HCG sample contains more early-type galaxies than the field, because it is known that H II nuclei are rarer in early-type galaxies than in later ones. (3) Applying a correction to this morphological bias to the HCG sample, we find that there is no statistically significant difference in the frequency of occurrence of emission-line galaxies between the HCGs and the field. This implies that the dense galaxy environment in the HCGs does not affect the triggering of either the AGN activity and the nuclear starburst. We discuss some implications on the nuclear activity in the HCG galaxies.


Title:
^13CO (J=1-0) Depression in Luminous Starburst Mergers, Revisited
Authors:
Taniguchi, Yoshiaki; Ohyama, Youichi; Sanders, D. B.
Publication:
The Astrophysical Journal, Volume 522, Issue 1, pp. 214-219. (ApJ Homepage)
Publication Date:
09/1999
Origin:
APJ
ApJ Keywords:
GALAXIES: INTERACTIONS, GALAXIES: ISM, GALAXIES: STARBURST, RADIO LINES: GALAXIES
DOI:
10.1086/307650
Bibliographic Code:
1999ApJ...522..214T

Abstract

It is known that merging galaxies with luminous starbursts and high far-infrared luminosities tend to have higher R_1-0=^12CO (J=1-0)/^13CO (J=1-0) integrated line intensity ratios (R_1-0~=20-50) than normal spiral galaxies (R_1-0~=5-15). Comparing far-infrared luminosities [L(FIR)] with those of ^12CO (J=1-0) and ^13CO (J=1-0) for a sample of normal and starburst galaxies, Taniguchi & Ohyama found that the observed high R_1-0 values for the luminous starburst mergers are attributed to their lower (by a factor of 3 on average) ^13CO line intensities. They suggested the following two possibilities: in the luminous starburst mergers (1) ^13CO is underabundant with respect to ^12CO, or (2) exitation and/or optical depth effects are responsible for the change in R_1-0. In this paper, we investigate the second possibility, using higher transition data of both ^12CO and ^13CO emission lines. Applying the same method proposed by Taniguchi & Ohyama to both ^12CO (J=2-1) and ^13CO (J=2-1), we find that ^13CO (J=2-1) is also depressed with respect to ^12CO (J=2-1). This suggests that the ^13CO gas may be underabundant in the high-R_1-0 starburst mergers, although we cannot rule out the possibility that excitation and optical depth effects are still affecting R_2-1, for example, as a result of the large velocity widths in the CO emission lines. Additional observations of both ^12CO and ^13CO lines at J>=3 are required to better constrain the conditions of the molecular gas in luminous starburst galaxies.


Title:
Redshifts of Galaxies around ARP 220 and Serendipitous Discovery of Three Star-forming Dwarf Galaxies at Redshift Z~0.5
Authors:
Ohyama, Youichi; Taniguchi, Yoshiaki; Hibbard, J. E.; Vacca, William D.
Publication:
The Astronomical Journal, Volume 117, Issue 6, pp. 2617-2625. (AJ Homepage)
Publication Date:
06/1999
Origin:
AJ
AJ Keywords:
GALAXIES: CLUSTERS: GENERAL, GALAXIES: DISTANCES AND REDSHIFTS, GALAXIES: INDIVIDUAL: NAME: ARP 220
DOI:
10.1086/300903
Bibliographic Code:
1999AJ....117.2617O

Abstract

We present redshift measurements of four faint galaxies around the archetypal ultraluminous infrared galaxy Arp 220. These galaxies have significantly higher redshifts (z~0.036-0.091) than that of Arp 220 (z~=0.018). Therefore, we conclude that they are background objects not physically related to Arp 220. Three of these faint galaxies located to the south of Arp 220 are a group of galaxies (or the brightest members in a cluster of galaxies) at z~=0.09, as has been suggested previously on the basis of their associated soft X-ray emission. We also report the serendipitous discovery of three additional galaxies at redshift z~0.5, found along one of the slit positions. All three galaxies exhibit an [O II] lambda3727 emission line. The spectrum of the brightest galaxy (m_R~=24.4) shows other strong emission lines: Mg II lambda2798, Hβ, [O III] lambda4959, and[O III] lambda5007. The emission-line properties of these galaxies as well as their intrinsically low luminosities (M_R>=-18.4) indicate that they are star-forming dwarf galaxies.


Title:
Optical versus Mid-infrared Spectroscopic Classification of Ultraluminous Infrared Galaxies
Authors:
Taniguchi, Yoshiaki; Yoshino, Akira; Ohyama, Youichi; Nishiura, Shingo
Publication:
The Astrophysical Journal, Volume 514, Issue 2, pp. 660-664. (ApJ Homepage)
Publication Date:
04/1999
Origin:
APJ
ApJ Keywords:
GALAXIES: ACTIVE, GALAXIES: SEYFERT, GALAXIES: STARBURST, INFRARED: GALAXIES
DOI:
10.1086/306992
Bibliographic Code:
1999ApJ...514..660T

Abstract

The origin of the huge infrared luminosities of ultraluminous infrared galaxies (ULIGs) is still in question. Recently, Genzel and colleagues performed a mid-infrared (MIR) spectroscopic survey of a large number of ULIGs and found the major energy source in them to be massive stars formed during recent starburst activity; ~70%-80% of the sample are predominantly powered by starbursts. However, previous optical spectroscopic observations classified the majority of ULIGs either as Seyferts or as LINERs. In order to reconcile this difference, we compare types of emission-line activity for a sample of ULIGs that have been observed in both optical and MIR. We confirm the results of previous studies that the majority of ULIGs classified as LINERs on the basis of optical emission-line diagnostics turn out to be starburst-dominated galaxies on the basis of MIR diagnostics. Since MIR spectroscopy can probe the more heavily reddened, inner parts of the ULIGs, and since it is quite unlikely that the inner parts are powered by starbursts while the outer parts are powered by nonstellar ionization sources, the most probable resolution of the dilemma is that the optical emission-line nebulae with LINER properties are powered predominantly by shock heating driven by superwind activity; i.e., blast waves driven by the collective effect of a large number of supernovae in the central region of galaxy mergers.


Title:
What Controls the Star Formation in Luminous Starburst Mergers?
Authors:
Taniguchi, Yoshiaki; Ohyama, Youichi
Publication:
The Astrophysical Journal, Volume 509, Issue 2, pp. L89-L92. (ApJ Homepage)
Publication Date:
12/1998
Origin:
APJ
ApJ Keywords:
GALAXIES: STARBURST, ISM: MOLECULES, STARS: FORMATION
DOI:
10.1086/311779
Bibliographic Code:
1998ApJ...509L..89T

Abstract

In order to understand what controls the star formation process in luminous starburst mergers (e.g., NGC 6240, Arp 220, and so on), we investigate observational properties of two samples of high-luminosity starburst galaxies mapped in CO J=1-0 independently using both the Owens Valley Radio Observatory (Scoville et al.) and the IRAM interferometer (Downes & Solomon). We find that the surface density of far-infrared luminosity, Sigma(FIR), is proportional linearly to the H_2 surface mass density, Sigma(H_2), for the two samples; Sigma(FIR)~Sigma(H_2)^1.01+/-0.06 with a correlation coefficient of 0.96. It is often considered that Sigma(FIR) provides a good measure of the star formation rate per unit area, Sigma(SFR). It is also known that molecular gas is dominated in circumnuclear regions in the luminous starburst mergers; i.e., Sigma(gas)~=Sigma(H_2). Therefore, the above relationship suggests a star formation law; Sigma(SFR)~Sigma(gas). We suggest that this star formation law favors the gravitational instability scenario rather than the cloud-cloud collision one.


Title:
An Origin of the Huge Far-Infrared Luminosity of Starburst Mergers
Authors:
Taniguchi, Yoshiaki; Ohyama, Youichi
Publication:
The Astrophysical Journal, Volume 508, Issue 1, pp. L13-L16. (ApJ Homepage)
Publication Date:
11/1998
Origin:
APJ
ApJ Keywords:
GALAXIES: STARBURST, ISM: DUST, EXTINCTION, ISM: MOLECULES
DOI:
10.1086/311728
Bibliographic Code:
1998ApJ...508L..13T

Abstract

Recently Taniguchi and Ohyama found that the higher ^12CO to ^13CO integrated intensity ratios at a transition J=1-0, R=I(^12CO)/I(^13CO)>~20, in a sample of starburst merging galaxies such as Arp 220 are mainly attributed to the depression of ^13CO emission with respect to ^12CO. Investigating the same sample of galaxies analyzed by Taniguchi and Ohyama, we find that there is a tight, almost linear correlation between the dust mass and ^13CO luminosity. This implies that dust grains are also depressed in the high-R starburst mergers, leading to the higher dust temperature (T_d) in them because of the relative increase in the radiation density. Nevertheless, the average dust mass (M_d) of the high-R starburst mergers is significantly higher than that of non-high-R galaxies. This is naturally understood because the galaxy mergers could accumulate a lot of dust grains from their progenitor galaxies together with the supply of dust grains formed newly in the star-forming regions. Since L(FIR) ~M_dT^5_d given the dust emissivity law S_nu~lambda^-1, the increases in both M_d and T_d explain well why the starburst mergers are so bright in the far-infrared. We discuss the important role that the superwind activity plays in destroying dust grains as well as dense gas clouds in the central region of mergers.


Title:
^13CO (J = 1-0) Depression in Luminous Starburst Mergers
Authors:
Taniguchi, Yoshiaki; Ohyama, Youichi
Publication:
The Astrophysical Journal, Volume 507, Issue 2, pp. L121-L124. (ApJ Homepage)
Publication Date:
11/1998
Origin:
APJ
ApJ Keywords:
GALAXIES: STARBURST, ISM: MOLECULES, GALAXIES: QUASARS: EMISSION LINES
DOI:
10.1086/311696
Bibliographic Code:
1998ApJ...507L.121T

Abstract

It is known that the class of luminous starburst galaxies tends to have higher R=^12CO (J=1-0)/^13CO (J=1-0) integrated line intensity ratios (R>20) than normal spiral galaxies (R~10). Since most previous studies investigated only R, it remains uncertain whether the luminous starburst galaxies are overabundant in ^12CO or underabundant in ^13CO. Here we propose a new observational test to examine this problem. Our new test is to compare far-infrared luminosities [L(FIR)] with those of ^12CO and ^13CO [L(^12CO) and L(^13CO), respectively]. It is shown that there is a very tight correlation between L(^12CO) and L(FIR), as found in many previous studies. However, we find that the ^13CO luminosities of the high-R galaxies are lower by a factor of 3 on average than those expected from the correlation for the remaining galaxies with ordinary R values. Therefore, we conclude that the observed high R values for the luminous starburst galaxies are attributed to their lower ^13CO line intensities.


Title:
Molecular Gas in the Poststarburst Galactic Nucleus of NGC 4736
Authors:
Shioya, Yasuhiro; Tosaki, Tomoka; Ohyama, Youichi; Murayama, Takashi; Yamada, Toru; Ishizuki, Sumio; Taniguchi, Yoshiaki
Affiliation:
AA(Astronomical Institute, Faculty of Science, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578; (YS):; and Center for Interdisciplinary Research, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578), AB(Gunma Astronomical Observatory, 1-18-7 Ohdomo, Maebashi, Gunma 371-0847), AC(Gunma Astronomical Observatory, 1-18-7 Ohdomo, Maebashi, Gunma 371-0847), AD(Gunma Astronomical Observatory, 1-18-7 Ohdomo, Maebashi, Gunma 371-0847), AE(Astronomical Institute, Faculty of Science, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578), AF(Nobeyama Radio Observatory, National Astronomical Observatory, Minamimaki, Minamisaku, Nagano 384-1305), AG(Astronomical Institute, Faculty of Science, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578})
Publication:
Publ. of the Astronomical Society of Japan, v.50, p.317-323. (PASJ Homepage)
Publication Date:
06/1998
Origin:
PASJ
PASJ Keywords:
GALAXIES: ACTIVE, GALAXIES: EVOLUTION, GALAXIES: INDIVIDUAL (NGC 4736), STARS: FORMATION
Bibliographic Code:
1998PASJ...50..317S

Abstract

We present (12) CO (J=1--0) observations of the poststarburst nucleus of NGC 4736. Although star in the nuclear region is currently inactive, there is a substantial amount of molecular gas, ~ 10(7 MO ) , in the central ~ 300 pc region. Comparing the observed molecular-gas surface density with the threshold gas density for star formation proposed by Kennicutt (1989, AAA 50.157.264), we find that the nuclear gas disk is stable for gravitational instability. We discuss possible scenarios for the nuclear starburst evolution of NGC 4736 in terms of either bar-driven instability fueling or minor-merger driven fueling (or triggering).


Title:
Near-Infrared Spectroscopy of the High-Redshift Quasar S4 0636+68 at Z = 3.2
Authors:
Murayama, Takashi; Taniguchi, Yoshiaki; Evans, Aaron S.; Sanders, D. B.; Ohyama, Youichi; Kawara, Kimiaki; Arimoto, Nobuo
Affiliation:
AA(Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan; , ), AB(Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan; , ), AC(Department of Astronomy, Mail Stop 105-24, California Institute of Technology, Pasadena, CA 91125; ), AD(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822; ), AE(Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan; ), AF(Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , ), AG(Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; , )
Publication:
The Astronomical Journal, Volume 115, Issue 6, pp. 2237-2243. (AJ Homepage)
Publication Date:
06/1998
Origin:
AJ
AJ Keywords:
GALAXIES: QUASARS: EMISSION LINES, GALAXIES: QUASARS: INDIVIDUAL: ALPHANUMERIC: S4 0636+68
DOI:
10.1086/300352
Bibliographic Code:
1998AJ....115.2237M

Abstract

We present near-infrared (observed frame) spectra of the high-redshift quasar S4 0636+68 at z = 3.2, which was previously thought to be one of a group of ``strong'' Fe ii emitters [i.e., F(Fe ii lambdalambda4434-4684)/F(Hβ) > 1]. Our K-band spectrum clearly shows emission lines of Hβ and [O iii] lambdalambda4959, 5007, as well as optical Fe ii emission. Our computed value of F(Fe ii lambdalambda4434-4684)/F(Hβ) ~= 0.8 for S4 0636+68 is less than previously thought and, in fact, is comparable to values found for radio-loud, flat-spectrum, low-z quasars. Therefore S4 0636+68 appears not to be a strong optical Fe ii emitter. Although more than half (5/8) of the high-z quasars observed to date are still classified as strong optical Fe ii emitters, their Fe ii/Hβ ratios, for the most part, follow the same trend as do those of low-z quasars, i.e., an anticorrelation in EW(Fe ii)/EW(Hβ) versus EW([O iii])/EW(Hβ), with radio-loud quasars having a mean value of EW(Fe ii)/EW(Hβ) approximately half that of radio-quiet quasars at comparable values of EW([O iii])/EW(Hβ).


Title:
Molecular Gas Superwind from the Face-On Wolf-Rayet Galaxy Markarian 1259
Authors:
Ohyama, Youichi; Taniguchi, Yoshiaki
Publication:
Astrophysical Journal Letters v.498, p.L27 (ApJ Homepage)
Publication Date:
05/1998
Origin:
APJ
ApJ Keywords:
GALAXIES: INDIVIDUAL NAME: MARKARIAN 1259, GALAXIES: STARBURST, ISM: MOLECULES
DOI:
10.1086/311299
Bibliographic Code:
1998ApJ...498L..27O

Abstract

We report the results of 12 CO ( J=1-0 ) mapping observations of the Wolf-Rayet starburst galaxy Markarian 1259, which has optical evidence for the superwind seen from a nearly pole-on view. The CO emission is detected in the central 4 kpc region. The nuclear CO spectrum shows a blueshifted ( Delta V~=-27 km s ^{-1} ) broad ( {FWHM}~=114 km s ^{-1} ) component as well as a narrow one ( {FWHM}~=68 km s ^{-1} ). The off-nuclear CO spectra also show the single-peaked broad component ( {FWHM}~=100 km s ^{-1} ). The single-peaked CO profiles of both the nuclear and off-nuclear regions may be explained if we introduce a CO gas disk with a velocity dispersion of ~100 km s ^{-1} . If this gas disk were extended up to a few kiloparsecs in radius, we may explain the wide line widths of the off-nuclear CO emission. Alternatively, we may attribute the off-nuclear CO emission to the gas associated with the superwind. However, if all the CO gas moves along the biconical surface of the superwind, the CO spectra would show double-peaked profiles. Hence, the single-peaked CO profiles of the off-nuclear regions may be explained by the idea that the morphology and/or velocity field of the molecular gas superwind are more complex, as suggested by hydrodynamical simulations.


Title:
Unusual Emission-Line Regions in the Tidal Arm of NGC 7318B in Stephan's Quintet
Authors:
Ohyama, Youichi; Nishiura, Shingo; Murayama, Takashi; Taniguchi, Yoshiaki
Publication:
Astrophysical Journal Letters v.492, p.L25 (ApJ Homepage)
Publication Date:
01/1998
Origin:
APJ
ApJ Keywords:
GALAXIES: INTERACTIONS, GALAXIES: INDIVIDUAL NGC NUMBER: NGC 7318B, ISM: SUPERNOVA REMNANTS, RADIO CONTINUUM: ISM
DOI:
10.1086/311086
Bibliographic Code:
1998ApJ...492L..25O

Abstract

We report the optical spectroscopic discovery of two unusual emission-line regions in the tidal arm of a galaxy, NGC 7318B, that belongs to Stephan's Quintet. They are associated spatially with the unusual radio continuum emission discovered between the two galaxies NGC 7318B and NGC 7319. Taking account of both the large velocity widths of the emission lines, ~900 km s ^{-1} , and the strong [S II] lambda lambda 6717, 6731 emission with respect to H alpha emission, we identify them as optical emission-line filaments of supernova remnants (SNRs) traced by the radio continuum and soft X-ray emission. Our narrowband H alpha imaging shows that the unusual emission-line regions are indeed parts of the ionized bubble associated with one radio continuum peak. The required number of SNRs is estimated to be ~105-106 on the basis of the H alpha , radio, and soft X-ray luminosities. Since there is no optical counterpart like a star cluster, it is suggested that ~105-106 supernova events occurred nearly simultaneously in this region several times 106 yr ago.


Title:
A New Superwind Wolf-Rayet Galaxy Markarian 1259
Authors:
Ohyama, Youichi; Taniguchi, Yoshiaki; Terlevich, Roberto
Publication:
Astrophysical Journal Letters v.480, p.L9 (ApJ Homepage)
Publication Date:
05/1997
Origin:
APJ
ApJ Keywords:
GALAXIES: INDIVIDUAL NAME: MARKARIAN 1259, GALAXIES: STARBURST, STARS: WOLF-RAYET
DOI:
10.1086/310615
Bibliographic Code:
1997ApJ...480L...9O

Abstract

We report the discovery of a starburst-driven wind (superwind) from the starburst nucleus galaxy Mrk 1259. The estimated number ratio of Wolf-Rayet (WR) to O stars amounts to ~=0.09. While the nuclear emission-line region is due to the usual photoionization by massive stars, the circumnuclear emission-line regions show anomalous line ratios that can be due to cooling shocks. Since the host galaxy seems to be a face-on disk galaxy and the excitation conditions of the circumnuclear emission-line regions show spatial symmetry, we consider that we are seeing the superwind nearly from a pole-on view. Cooling shock models may explain the observed emission-line ratios of the circumnuclear regions, although a factor of 2 overabundance of nitrogen is necessary. All these suggest that the high-mass--enhanced starburst occurred ~5 x 106 yr ago in the nuclear region of Mrk 1259.


Title:
The Poststarburst Galactic Nucleus of NGC 4736
Authors:
Taniguchi, Yoshiaki; Ohyama, Youichi; Yamada, Toru; Mouri, Hideaki; Yoshida, Michitoshi
Publication:
Astrophysical Journal v.467, p.215 (ApJ Homepage)
Publication Date:
08/1996
Origin:
APJ; NED
ApJ Keywords:
GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4736, GALAXIES: NUCLEI, GALAXIES: STARBURST, GALAXIES: STELLAR CONTENT
DOI:
10.1086/177596
Bibliographic Code:
1996ApJ...467..215T

Abstract

We present optical spectroscopic analysis of the nuclear region of the nearby Sab galaxy NGC 4736 in which the strong Balmer absorption lines are observed, providing evidence for a past starburst event. In order to study both the present-day stellar populations and the emission-line activity in the nucleus, we have made the stellar population synthesis and found that a luminous starburst occurred 1 x 10^9^ years ago in the nuclear region. Correcting for the effect of the underlying stellar absorption features, we find that the ionized gas in the nuclear region shows the very marginal nature between an ordinary H II region and a low- ionization nuclear emission-line region (LINER). The absorption-corrected Hα luminosity amounts only to 1.3 x 10^38^ ergs s^-1^, which is lower than that of the Galactic H II region W49. If we consider a case of the photoionization by massive stars, only six O6 stars are responsible for the ionization in the central 37 pc x 60 pc region. We also study the emission-line ratio properties of the classical LINERs in the literature. The LINERs tend to show a sequence in the excitation diagram: the positive correlation between log [O III] λ5007/Hβ and log [N II] λ6583/Hα. This correlation may be attributed to a scatter of the relative strength of stellar Balmer absorption to nebular Balmer emission among the sample. Therefore, we call attention to the possibility that some LINERs may in fact be poststarburst galaxies rather than genuine active galactic nuclei.


Title:
Optical spectra of the supernova 1993J in M81
Authors:
Taniguchi, Yoshiaki; Murayama, Takashi; Sato, Yasunori; Yadoumaru, Yasushi; Ohyama, Youichi; Kosugi, George; Yoshida, Michitoshi; Kurakami, Tomio
Affiliation:
AA(Tohoku Univ., Sendai, Japan), AB(Tohoku Univ., Sendai, Japan), AC(Tohoku Univ., Sendai, Japan), AD(Tohoku Univ., Sendai, Japan), AE(Tohoku Univ., Sendai, Japan), AF(Kyoto Univ., Japan), AG(Kyoto Univ., Japan), AH(Okayama Astrophysical Observatory, Japan)
Publication:
PASJ: Publications of the Astronomical Society of Japan (ISSN 0004-6264), vol. 45, no. 3, p. L43-L46. (PASJ Homepage)
Publication Date:
06/1993
Category:
Astrophysics
Origin:
STI
NASA/STI Keywords:
STELLAR SPECTRA, SUPERNOVAE, VISIBLE SPECTRUM, EMISSION SPECTRA, STELLAR SPECTROPHOTOMETRY
Bibliographic Code:
1993PASJ...45L..43T

Abstract

We present the optical spectra of supernova 1993J which occurred in M81. The observations were made on 1993 March 31, covering the wavelength region between 4500 and 9000 A. Although there are no remarkable emission features, weak emission lines at both lambda 5858 and 6559 A exist in the spectra. These emission lines can probably be attributed to He I lambda 5876 A and H-alpha lambda 6563 A, respectively. The He I emission is blueshifted by 800 km/s with respect to the H I velocity of the position of SN 1993J.


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