Galaxy clustering and galaxy
clusters from the UKIDSS DXS

Abstract

Recent wide and deep surveys allow us to investigate the large scale structure of the
Universe at high redshift. We present studies of the clustering of high redshift galaxies
and galaxy clusters, using reprocessed UKIDSS DXS catalogues. The UKIDSS
DXS is one of the deepest near-IR surveys to date and provides sufficient samples
of the distant Universe.
Firstly we measure the angular correlation function of high redshift red galaxies
which are Extremely Red Objects (EROs) and Distant Red Galaxies (DRGs) in
Chapters 3 and 4 from DXS SA22 and Elais-N1 fields. We found that their angular
correlation functions can be described by a broken power-law. Thus we estimated
clustering properties on small and large scales separately. Then we found that
red or bright samples are more strongly clustered than those having the opposite
characteristics. In addition old, passive EROs are found to be more clustered than
dusty, star-forming EROs. The effect of cosmic variance on angular clustering was
also investigated.
Chapter 5 describes the halo modelling for the angular clustering of EROs. EROs
reside in in dark matter haloes having > 1012.9h−1M, and have a bias of 1.93 at z =
1.12 and 3.17 at z = 1.55. From a direct comparison between the observed clustering
and the cosmological model, they show good agreement. However the cosmological
simulation may predict too many red satellites, especially at high redshfit.
In Chapter 6, we present the details of our cluster detection algorithm based
on the red sequence technique. This algorithm successfully found published galaxy
clusters in the DXS Elais-N1 field. We also found many overdensities in the DXS
SA22 field. Two prominent galaxy clusters were confirmed by spectroscopic observations,
and we identified a supercluster candidate. Finally the clustering strength
of candidate galaxy clusters showed good agreement with previous results and was
consistent with the ΛCDM prediction.
In the near future the full DXS catalogue will provide an opportunity to detect
various high redshift populations. With other advanced surveys, it will be possible
to investigate more details of the large scale structure of the Universe.