Related papers: Forming Early-type Galaxies in Groups Prior to Clu…
Massive galaxy clusters are now found as early as 3 billion years after the Big Bang, containing stars that formed at even earlier epochs. The high-redshift progenitors of these galaxy clusters, termed 'protoclusters', are identified in…
We investigate the formation and morphological evolution of the first galaxies in the cosmic morning ($10 \gtrsim z \gtrsim 4$) using the Horizon Run 5 (HR5) simulation. For galaxies above the stellar mass $M_{\star, {\rm min}} = 2\times…
We study the photometric and spectral properties of 39320 early-type galaxies within the SDSS, as a function of both local environment and redshift. The distance to the nearest cluster of galaxies and the distance to the 10th nearest…
We test the hypothesis that metal-poor globular clusters form within disk galaxies at redshifts z>3. Numerical simulations demonstrate that giant gas clouds, which are cold and dense enough to produce massive star clusters, assemble…
We present an extremely deep CO(1-0) observation of a confirmed $z=1.62$ galaxy cluster. We detect two spectroscopically confirmed cluster members in CO(1-0) with $S/N>5$. Both galaxies have log(${\cal M_{\star}}$/\msol)$>11$ and are gas…
The abundance of elliptical, S0 and spiral galaxies in clusters is presented as a function of redshift comparing the results of the HST distant cluster studies with new data at z~0.2 and with the standard local comparison samples. This…
We present a model to investigate the formation and evolution of cluster galaxies using cosmological N-body simulations. The N-body simulations are used to make merging history trees of dark halos. Gas cooling, star formation, supernova…
The properties of K-band selected galaxies (K_AB<24) in the z = 3.09 SSA22 protocluster field are studied. 430 galaxies at 2.6 < z_phot < 3.6 are selected as potential protocluster members in a 112 arcmin^2 area based on their photometric…
A magnitude limited sample of nearly 9000 early-type galaxies, in the redshift range 0.01 < z < 0.3, was selected from the Sloan Digital Sky Survey using morphological and spectral criteria. The Fundamental Plane relation in this sample is…
In the context of pre-processing -- a scenario in which galaxies quench their star formation within substructures before falling into clusters -- we investigate the impact of environment on the physical and morphological properties of…
We study luminosity and morphology segregation of over 3000 cluster galaxies in an ensemble cluster of 59 rich, nearby galaxy clusters observed in the ESO Nearby Cluster Survey (ENACS). Within this sample we identify those galaxies that are…
The study of the ages of early-type galaxies and their dependence on galaxy mass and environment is crucial for understanding the formation and early evolution of galaxies. We review recent works on the M/L ratio evolution, as derived from…
We present new results of a program to study the detailed morphologies of galaxies in intermediate redshift clusters and hence understand the physical origin of the enhanced star formation in these environments at earlier epochs. Deep, high…
We present a high spatial-resolution HST/NICMOS imaging survey in the field of a known protocluster surrounding the powerful radio galaxy MRC1138-262 at z=2.16. Previously, we have shown that this field exhibits a substantial surface…
We trace the evolution of central galaxies in three ~10^13 M_sun galaxy groups simulated at high resolution in cosmological hydrodynamical simulations. The evolution in the group potential leads, at z=0, to central galaxies that are…
We combine morphological classifications from deep HST imaging of a sample of 3 clusters at z=0.31 and a further 9 clusters at z=0.37-0.56 with existing spectroscopic observations of their E and S0 populations, to study the relative…
We investigate the assembly of groups and clusters of galaxies using the Millennium dark matter simulation and the associated gas simulations and semi-analytic catalogues of galaxies. In particular, in order to find an observable quantity…
The nature of Compact Groups (CGs) is investigated by comparing the luminosities and morphologies of CG galaxies, CG Neighbours and Isolated galaxies. CGs turn out to include more early type galaxies than Isolated galaxies and fewer…
The environment plays a critical role in galaxy evolution, with galaxy clusters and their infall regions offering diverse conditions that shape galaxies before they enter the dense cluster core, a process known as ``pre-processing''.…
Using deep HST ACS imaging and VLT FORS2 spectra, we determined the velocity dispersions, effective radii and surface brightnesses for four early-type galaxies in the $z=1.237$ cluster \cl. All four galaxies are massive, $> 10^{11}…