12 December 2008
Johan Richard (ICC, University of Durham)
"Strong-lensing analysis of the most massive lensing clusters"
Strong gravitational lensing is a unique tool to model with great accuracy
the inner mass distribution of massive galaxy clusters.
In particular, clusters with large Einstein radii provide a wealth of
multiply imaged systems in the cluster core.
Measuring the redshift of these multiple images provide strong constraints
to determine precisely the shape of the central dark matter profile.
I will present some results obtained during recent spectroscopic
surveys with Keck/LRIS, aiming at confirming and measuring spectroscopic
redshifts of many multiple images. The main part of the talk will be
focused on the mass distribution derived from strong lensing, in
particular with the results on the clusters Abell 1689 and Abell 1703.
I will then present a second application of this sectroscopic dataset,
which is to study the population of background galaxies lensed by the
clusters, taking benefit from the large magnification factors (typically
1 to 3 magnitudes) occuring on these objects.