Related papers: The Group Evolution Multiwavelength Study (GEMS): …
Isolated compact groups of galaxies (CGs) present a range of dynamical states, group velocity dispersions, and galaxy morphologies with which to study galaxy evolution, particularly the properties of gas both within the galaxies and in the…
X-ray selected surveys of clusters of galaxies can distinguish between hierarchical models of the growth of structure in the Universe. Here we present the first results from an X-ray selected, flux and surface brightness limited deep survey…
We report on the X-ray and optical observations of galaxy groups selected from the 2dfGRS group catalog, to explore the possibility that galaxy groups hosting a giant elliptical galaxy and a large optical luminosity gap present between the…
We analyse a Far InfraRed (FIR) catalogue of galaxies at 60 microns with a flux limit of approx. 110 mJy, extracted from a deep subsample of the IRAS Faint Source Survey. Monte-Carlo simulations and optical identification statistics are…
In this letter, we present a new determination of the local (z<0.09) X-ray luminosity function (XLF) using a large, statistical sample of 294 Abell clusters and the ROSAT All-Sky-Survey. Given our large sample size, we have reduced errors…
We present soft (0.5-2 keV) X-ray luminosity functions (XLFs) in the Great Observatories Origins Deep Survey (GOODS) fields, derived for galaxies at z~0.25 and 0.75. SED fitting was used to estimate photometric redshifts and separate galaxy…
We present the Complete Local-Volume Groups Sample (CLoGS), a statistically complete optically-selected sample of 53 groups within 80 Mpc. Our goal is to combine X-ray, radio and optical data to investigate the relationship between member…
Properties of the hot intracluster and intragroup medium are mostly set by the underlying gravitational potential well, although complex astrophysical processes at play during their buildup may leave a significant imprint. Observational…
The dependence of the luminosity function of cluster galaxies on the evolutionary state of the parent cluster is still an open issue, in particular as concern the formation/evolution of the brightest cluster galaxies. We plan to study the…
We have acquired deep, H-band, imaging for a sample of 286 Virgo cluster galaxies with B <= 16 mag and extracted surface photometry from optical g,r,i,z Sloan Digital Sky Survey images of 742 Virgo Cluster Catalog galaxies, including those…
We have used the 30'x30' Hubble Space Telescope image mosaic from the Galaxy Evolution from Morphology and SEDs (GEMS) project in conjunction with the COMBO-17 deep photometric redshift survey to define a sample of nearly 1500 galaxies with…
The luminosity function of galaxies is derived from a cosmological hydrodynamic simulation of a Lambda cold dark matter (CDM) universe with the aid of a stellar population synthesis model. At z=0, the resulting B band luminosity function…
We study the X-ray luminosity function (XLF) of low mass X-ray binaries (LMXB) in the nearby early-type galaxy Centaurus A, concentrating primarily on two aspects of binary populations: the XLF behavior at the low luminosity limit and…
We measure the evolution of the rest-frame K-band Fundamental Plane from z=1 to the present by using IRAC imaging of a sample of early-type galaxies in the Chandra Deep Field-South at z~1 with accurately measured dynamical masses. We find…
While in the hierarchical model of structure formation, groups of galaxies are believed to be the scaled-down version of clusters of galaxies, a similarity breaking in the fundamental laws may occur on the group scale, reflecting a…
We investigate the relation between the projected morphology (b/a) and the velocity dispersion (sigma_v) of groups of galaxies using two recently compiled group catalogs, one based on the 2MASS redshift survey and the other on the SDSS Data…
We found a new, very compact group of galaxies characterized by a median projected separation between galaxies of 5.2/h kpc and a very low velocity dispersion. All the observed member galaxies show emission line spectra and a disturbed…
We use the weak gravitational lensing effect to study the mass distribution and dynamical state of a sample of 24 X-ray luminous clusters of galaxies ($0.05<z<0.31$) observed with the VLT-FORS1 under homogeneous sky conditions and…
We present the results of a dynamical analysis of three rich, X-ray luminous galaxy clusters, Abell 222, Abell 223 and Abell 520, that are at intermediate redshifts. Our study is based on radial velocities for 71 cluster members,…
We analyse the Lx-sigma relation for the new Mulchaey et al. group Atlas. We find that once we take into account the possible statistical bias introduced by the cutoff in luminosity, we recover a relation which is consistent with that of…