Constraining the cosmic microwave background temperature evolution and the population and structure of galaxy clusters and groups from the South Pole Telescope and the Planck Surveyor

Galaxy clusters, the massive systems host hundreds of galaxies, are
invaluable cosmological probes and astrophysical laboratories.
Besides these fascinating galaxies, the concentration of dark
matter creates a deep gravitational potential well, where even
light passing by is bended and the background image is distorted.
The baryonic gas falling into the potential well is heated up to
more than 10^7 K that free electrons start to emitting in X-ray.
Observing those phenomena leads to a throughout understanding of
gravity, particle physics and hydrodynamics. In addition, residing
on the top of the density perturbations, clusters are sensitive to
the initial condition of the Universe, such that they are
complimentary tools for cosmology studies. In this thesis we first
introduce the basic framework of the Universe and supporting
observational evidence. Following that, we sketch the principle to
use clusters for cosmology study via their redshift and mass
distribution. However cluster mass is not a direct observable, so
we need to estimate it by other channels. We briefly exhibit
cluster observations in optical, X-ray and microwave bands and
discuss the challenges in estimating the underlying cluster mass
with them. After this introduction, we present our results on three
aspects of the cluster cosmology study. First, we present a study
of Planck Sunyaev-Zel’dovich effect (SZE) selected galaxy cluster
candidates using Panoramic Survey Telescope & Rapid Response
System (Pan-STARRS) imaging data. To fulfil the strength of SZE
survey, the redshifts of clusters are required. In this work we
examine 237 Planck cluster candidates that have no redshift in the
Planck source catalogue. Among them, we confirmed 60 galaxy
clusters and measure their redshifts. For the remaining sample, 83
candidates are so heavily contaminated by stars due to their
location near the Galactic plane that we do not identify galaxy
members and assign reliable redshifts. For the rest 94 candidates
we find no optical counterparts. By examining with 150 Planck
confirmed clusters with spectroscopy redshifts, our redshift
estimations have an accuracy of σ_{z/(1+z)}~0.022. Scaling for the
already published Planck sample, we expect the majority of the
unconfirmed candidates to be noise fluctuations, except a few at
high redshift that the Pan-STARRS1 (PS1) data are not sufficiently
deep for confirmation. Thus we use the depth of the optical imaging
for each candidate together with a model of the expected galaxy
population for a massive cluster to estimate a redshift lower
limit, beyond which we would not have expected to detect the
optical counterpart. Second, we use 95GHz, 150GHz, and 220GHz
observations from South Pole Telescope (SPT) to study the SZE
signatures of a sample of 46 X-ray selected groups and clusters
drawn from ~6 deg^2 of the XMM-Newton Blanco Cosmology Survey
(XMM-BCS). The wide redshift range and low masses make this
analysis complementary to previous studies. We develop an analysis
tool that using X-ray luminosity as a mass proxy to extract
selection-bias corrected constraints on the SZE significance- and
Y_{SZ}-mass relations. The SZE significance- mass relation is in
good agreement with an extrapolation of the relation obtained from
high mass clusters. However, the fit to the Y_{SZ}-mass relation at
low masses, while in agreement with the extrapolation from high
mass SPT sample, is in tension at 2.8σ with the constraints from
the Planck sample. We examine the tension with the Planck relation,
discussing sample differences and biases that could contribute. We
also analyse the radio galaxy point source population in this
ensemble of X-ray selected systems. We find 18 of our systems have
1 GHz Sydney University Molonglo Sky Survey (SUMSS) sources within
2 arcmin of the X-ray centre, and three of these are also detected
at significance >4 by SPT. Among these three, two are associated
with the brightest cluster galaxies, and the third is a likely
unassociated quasar candidate. We examined the impact of these
point sources on our SZE scaling relation result and find no
evidence of biases. We also examined the impact of dusty galaxies.
By stacking the 220 GHz data, we found 2.8σ significant evidence of
flux excess, which would correspond to an average underestimate of
the SZE signal that is (17±9) % in this sample of low mass systems.
Finally we predict a factor of four to five improvements on these
SZE mass-observable relation constraints based on future data from
SPTpol and XMM-XXL. In the end we present a study using clusters as
tools to probe deviations from adiabatic evolution of the Cosmic
Microwave Background (CMB) temperature. The expected adiabatic
evolution is a key prediction of standard cosmology. We measure the
deviation of the form T(z)=T_0(1+z)^{1-α} using measurements of the
spectrum of the SZE with SPT. We present a method using the ratio
of the SZE signal measured at 95 and 150 GHz in the SPT data to
constrain the temperature of the CMB. We validate that this
approach provides unbiased results using mock observations of
cluster from a new set of hydrodynamical simulations. Applying this
method to a sample of 158 SPT-selected clusters, we measure
α=0.017^{+0.030}_{−0.028} consistent with the standard model
prediction of α=0. Combining with other published results, we find
α=0.005±0.012, an improvement of ~ 10% over published constraints.
This measurement also provides a strong constraint on the effective
equation of state, w_{eff}=−0.994±0.010, which is presented in
models of decaying dark energy.