Mass and Light distributions in Clusters of Galaxies - Henry A ...

Chapter 1
Introduction
Clusters of galaxies are the most massive virialized objects in the Universe,
and as such they gravitationally “pull” on the light traveling from galaxies
lying behind them. This is an example of an effect called “gravitational
lensing”. It has prompted a wide field of research and was established as a
robust method to explore galaxy clusters. The dependence on various angular
distances of the lens system means cosmology can be diagnosed via lensing.
In the past decade, with the improvement of observational instruments, and
the development of codes, many clusters have been studied in great detail
with lensing.
The focus of my PhD was the study of mass and light properties of several
clusters, using observations of both ground-based and space-based telescopes.
I developed techniques to carefully isolate background galaxies for
a clean weak lensing measurement, and to identify the cluster based on its
dilution of the weak lensing signal. The reconstructed mass and light profiles
of the clusters, which were resolved with unprecedented accuracy and detail,
were used to explore inner cluster properties, as well as to be compared
with cosmological simulations of structure formation and test current cosmological
models. The quality of the data and the extensive analysis allowed
for a unique determination of the increment of the weak lensing signal with
redshift.
1