Related papers: Candidate fossil groups in the CFHTLS: a probabili…

Fossil groups (FGs) are groups or clusters of galaxies with a single, massive, central galaxy and with a clear lack of L* galaxies. The physical reason for their large magnitude gap (dm12) may arise from early FG formation, which allowed…

Using the Illustris cosmological simulation, we investigate the origin of fossil groups in the $M_{200}=10^{13}-10^{13.5}M_{\odot}/h$ mass regime. We examine the formation of the two primary features of fossil groups: the large magnitude…

We present a catalog of 129 X-ray galaxy groups, covering a redshift range 0.04<z<1.23, selected in the ~3 square degree part of the CFHTLS W1 field overlapping XMM observations performed under the XMM-LSS project. We carry out a…

Clusters of galaxies are at the intersection of cosmic filaments and are still accreting galaxies and groups along these preferential directions, but, because of their relatively low contrast on the sky, they are difficult to detect (unless…

We investigate the efficacy of using the cosmic web nodes identified by the DisPerSE topological filament finder to systematically identify galaxy groups in the infall regions around massive clusters. The large random motions and infall…

We present an X-ray follow-up, based on XMM plus Chandra, of six Fossil Group (FG) candidates identified in our previous work using SDSS and RASS data. Four candidates (out of six) exhibit extended X-ray emission, confirming them as true…

Fossil galaxy groups are spatially extended X-ray sources with X-ray luminosities above L_X,bol > 10^42 h_50^-2 ergs s^-1 and a central elliptical galaxy dominating the optical, the second-brightest galaxy being at least 2 magnitudes…

Recent wide-field imaging observations of the X-ray luminous cluster RDCSJ1252.9-2927 at z=1.24 uncovered several galaxy groups that appear to be embedded in filamentary structure extending from the cluster core. We make a spectroscopic…

We have started a study of luminosity functions of Fossil Group candidates in order to characterize the faint-end of their galaxy distribution. Here we report on results of nine of them from SDSS photometry.

The detection of low surface brightness galaxies beyond the Local Group poses significant observational challenges, yet these faint systems are fundamental to our understanding of dark matter, hierarchical galaxy formation, and cosmic…

We present a detailed study of fossil group candidates identified in "Last Journey", a gravity-only cosmological simulation covering a $(3.4\, h^{-1}\mathrm{Gpc})^3$ volume with a particle mass resolution of $m_p \approx 2.7 \times 10^9\,…

A small fraction of galaxies appear to reside in dense compact groups, whose inferred crossing times are much shorter than a Hubble time. These short crossing times have led to considerable disagreement about the dynamical state of these…

Cosmological LCDM simulations of 12 M_vir~10^14 Msun galaxy groups have been performed, invoking star formation, chemical evolution with non-instantaneous recycling, metallicity dependent radiative cooling, strong star-burst driven galactic…

At large redshifts, a cluster or group may be too distant for the galaxies within the cluster to be detected individually. However, the light from these ``undetected'' galaxies still modulates the surface brightness of the background sky.…

There is accumulating evidence that the faint end of the galaxy luminosity function might be very different in different locations. The luminosity function might be rising in rich clusters and flat or declining in regions of low density. If…

We exploit a new sample of around 400 bright dusty galaxies from the ALMA CHAMPS Large Program, together with the rich JWST multi-band data products in the COSMOS field, to explore and validate new selection methods for identifying dusty…

This study is part of the FOssil Groups Origin (FOGO) project which aims at carrying out a systematic and multiwavelength study of a large sample of fossil systems. Here we focus on the relation between the optical luminosity (Lopt) and…

We have compiled a sample of 67 nearby ($z$ < 0.15) clusters of galaxies, for which on average more than 150 spectroscopic members are available, and, by applying different methods to detect substructures in their galaxy distribution, we…

The most luminous galaxies in the blue passband have a larger correlation amplitude than L* galaxies. They do not appear to be preferentially located in rich clusters or groups, but a significant fraction of them seem to be in systems which…

Fossil galaxy groups are speculated to be old and highly evolved systems of galaxies that formed early in the universe and had enough time to deplete their $L^{*}$ galaxies through successive mergers of member galaxies, building up one…