相关论文: Characterizing the nature of Fossil Groups with XM…
We use SDSS-DR4 photometric and spectroscopic data out to redshift z~0.1 combined with ROSAT All Sky Survey X-ray data to produce a sample of twenty-five fossil groups (FGs), defined as bound systems dominated by a single, luminous…
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 use a set of twelve high-resolution N-body/hydrodynamical simulations in the $\Lambda$CDM cosmology to investigate the origin and formation rate of fossil groups (FGs), which are X-ray bright galaxy groups dominated by a large elliptical…
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 present a new sample of 25 fossil groups (FGs) at z < 0.1, along with a control sample of seventeen bright ellipticals located in non-fossil systems. Both the global properties of FGs (e.g. X-ray luminosity) as well as the photometric…
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…
Fossil groups (FGs) are galaxy aggregates with an extended and luminous X-ray halo, which are dominated by a very massive early-type galaxy and lack of L* objects. FGs are indeed characterized by a large magnitude gap between their central…
This paper presents both the result of a search for fossil systems (FSs) within the XMM Cluster Survey and the Sloan Digital Sky Survey and the results of a study of the stellar mass assembly and stellar populations of their fossil…
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…
(Abridged) Fossil systems are galaxy associations dominated by a relatively isolated, bright elliptical galaxy, surrounded by a group of smaller galaxies lacking L* objects. We analyzed the near-infrared photometric and structural…
(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…
We report on 2 fossil groups of galaxies at z=0.425 and 0.372 discovered in the Cosmic Evolution Survey (COSMOS) area. Selected as X-ray extended sources, they have total masses (M_200) of 1.9(+/-0.41)E13 and 9.5(+/-0.42)E13 M_sun,…
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…
The most accepted scenario for the origin of fossil groups (FGs) is that they are galaxy associations in which the merging rate was fast and efficient. These systems have assembled half of their mass at early epoch of the Universe,…
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 investigate the evolution of bright and faint galaxies in fossil and non-fossil groups. We used mock galaxies constructed based on the Millennium run simulation II. We identified fossil groups at redshift zero according to two different…
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 ten galaxy groups and clusters suggested in the literature to be "fossil system (FS)" based on \chandra\ observations. According to the $M_{500}-T$ and $L_{\rm X}-T$ relations, the gas properties of FSs are not physically distinct…
It has been a long-standing question whether fossil groups are just sampling the tail of the distribution of ordinary groups, or whether they are a physically distinct class of objects, characterized by an unusual and special formation…
We present MMT spectroscopic observations of two massive galaxy cluster candidates at redshift $z\sim0.07$ that show extended and diffuse X-ray emission in the ROSAT All Sky Survey (RASS) images. The targets were selected from a previous…