相关论文: RX J1548.9+0851, a fossil cluster?
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…
(Abridged) Fossil systems are group- or cluster-sized objects whose luminosity is dominated by a very massive central galaxy. In the current cold dark matter scenario, these objects formed hierarchically at an early epoch of the Universe…
The evolution of present-day fossil galaxy groups is studied in the Millennium Simulation. Using the corresponding Millennium gas simulation and semi-analytic galaxy catalogues, we select fossil groups at redshift zero according to the…
Fossil systems are defined to be X-ray bright galaxy groups with a 2-magnitude difference between their two brightest galaxies within half the projected virial radius,and represent an interesting extreme of the population of galaxy…
We present a detailed kinematical and dynamical study of the galaxy cluster RXCJ1111.6+4050 (RXCJ1111), at z = 0.0756 using 104 new spectroscopic redshifts of galaxies observed at the TNG 3.5m telescope and SDSS DR16 public archive. Our…
We present strong-lensing analyses of three galaxy clusters, RXJ2129.4+0009 (z=0.235), MS0451.6-0305 (z=0.55), and MACSJ2129.4-0741 (z=0.589), using the powerful combination of Hubble Space Telescope (HST) multi-band observations, and…
We present a combined optical and X-ray analysis of three optically selected X-ray bright groups with giant elliptical galaxies in the center. These massive ellipticals were targeted for XMM-Newton X-ray observations based on their large…
We study six groups and clusters of galaxies suggested in the literature to be `fossil' systems (i.e. to have luminous diffuse X-ray emission and a magnitude gap of at least 2 mag-R between the first and the second ranked member within half…
We present the results of a detailed analysis of galaxy properties along the red sequence in XMMU J1229+0151, an X-ray selected cluster at $z=0.98$ drawn from the HAWK-I Cluster Survey (HCS). Taking advantage of the broad photometric…
We report the discovery of seven new fossil systems in the 400d cluster survey. Our search targets nearby, $z\le0.2$, and X-ray bright, $L_X\ge 10^{43}$ erg sec$^{-1}$, clusters of galaxies. Where available, we measure the optical…
We report the discovery of 12 new fossil groups of galaxies, systems dominated by a single giant elliptical galaxy and cluster-scale gravitational potential, but lacking the population of bright galaxies typically seen in galaxy clusters.…
We present a sample of 47 spectroscopically confirmed members of RX J1347-1145, the most luminous X-ray cluster of galaxies discovered to date. With two exceptions, all the galaxies in this sample have red B-R colors and red spectral…
Fossil groups are considered the end product of natural galaxy group evolution in which group members sink towards the centre of the gravitational potential due to dynamical friction, merging into a single, massive, and X-ray bright…
The group of galaxies RXJ1340.6+4018 has approximately the same bolometric X-ray luminosity as other bright galaxy groups and poor clusters such as the Virgo cluster. However, 70% of the optical luminosity of the group comes from a dominant…
In the distant universe X-ray luminous clusters of galaxies are rare objects. Large area surveys are therefore needed to probe the high luminosity end of the cluster population at redshifts z >= 1. We correlated extended X-ray sources from…
XMMU J1229+0151 is a rich galaxy cluster with redshift z=0.975, that was serendipitously detected in X-rays within the scope of the XMM-Newton Distant Cluster Project. HST/ACS observations in the i775 and z850 passbands, as well as…
Fossil groups (FGs) have been discovered twenty-five years ago, and are now defined as galaxy groups with an X-ray luminosity higher than $10^{42}\ h_{50}^{-2}$ erg s$^{-1}$ and a brightest group galaxy brighter than the other group members…
We present Chandra snapshot observations of the first large X-ray sample of optically identified fossil groups. For 9 of 14 candidate groups, we are able to determine the X-ray luminosity and temperature, which span a range typical of large…
We have obtained a new high-resolution K'-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z=1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects.…
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…