Title: Gravitational Lensing in Galaxy Clusters

Abstract:

The light rays propagating from distant background sources are deflected by
the gravitational field of intervening mass concentrations, such as clusters of galaxies, 
leading to various gravitational lensing phenomena. 
Strong gravitational lensing accompanies highly magnified giant luminous arcs and/or multiple images 
of background sources in the dense central region of clusters.
Weak gravitational lensing is responsible for the weak shearing and magnification 
of the images of background sources, which can be observed to much larger angular separations
from the cluster center. A combination of strong and weak lensing, probing complementary angular scales, 
thus enables a full reconstruction of the cluster mass profile over a wide dynamic range 
from the dense central region (~0.01*R_vir) out to the cluster virial radius (R_vir). 
In this talk we will present a brief introduction to strong/weak gravitational lensing
as well as our recent work on cluster gravitational lensing, including results from
our lensing measurements of cluster mass profiles.