Related papers: Physically Detached "Compact Groups"
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 analyze compact groups of galaxies appearing in a galaxy formation simulation dominated by cold dark matter (omega_0=1, omega_{baryon}=0.1). The simulation uses an N-body code to model the behavior of the non-baryonic matter and smoothed…
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…
Compact groups (CGs) of galaxies are extreme environments for morphological transformations and the cessation of star formation. Though initially considered isolated, it is now recognised that many CGs are embedded in larger structures. We…
Mass segregation, a tendency of more massive galaxies being distributed closer to the cluster center, is naturally expected from dynamical friction, but its presence is still controversial. Using deep optical observations of 14 Abell…
The mass function of galaxies and clusters of galaxies can be derived observationally based on different types of observations. In this study we test if these observations can be combined to a consistent picture which is also in accord with…
[Abridged] We make use of a semi-analytic cosmological model that includes simple prescriptions for dust attenuation and emission to make predictions for the observable and physical properties of galaxies that may be detected by the…
We analyse a sample of about 2000 galaxies in 40 regular clusters, to look for evidence of segregation with respect to galaxy luminosities and morphological types. We find evidence of luminosity segregation for galaxies brighter than $M_R <…
A classification scheme for close pairs of galaxies is proposed. The scheme is motivated by the fact that the majority of apparent close pairs are in fact wide pairs in three-dimensional space. This is demonstrated by means of numerical…
New redshift surveys of galaxies in the field of compact groups have discovered a population of faint galaxies which act as satellites orbiting in the potential well of the bright group. Here we analyze the mass distribution of the groups…
A statistical method is developed to infer the typical density profiles of poor galaxy systems without resort to binning of data or assuming a given center to each system. The method is applied to the accordant redshift quartets in…
We discuss the merging rates in compact groups of 5 identical elliptical galaxies. All groups have the same mass and binding energy. We consider both cases with individual halos and cases where the halo is common to all galaxies and…
In order to constrain parameters in galaxy formation theories, especially those for a star formation process, we investigate cold gas in elliptical galaxies. We calculate the detection rate of cold gas in them using a semi-analytic model of…
Recent studies have shown that massive quiescent galaxies at high redshift are much more compact than present-day galaxies of the same mass. Here we compare the radial stellar density profiles and the number density of a sample of massive…
We give the first determination of the observed peculiar velocity distribution function for a representative sample of galaxies (within 50 Mpc (H=100) of the Local Group), which includes a wide range of clustering properties. We explore in…
Promising methods for studying galaxy evolution rely on optical emission line width measurements to compare intermediate-redshift objects to galaxies with equivalent masses at the present epoch. However, emission lines can be misleading. We…
Mergers of gas-poor galaxies, so-called dry mergers, may play a fundamental role in the assembly of the most massive galaxies, and therefore, in galaxy formation theories. Using the SDSS, we have serendipitously discovered a rare system in…
Massive, quiescent galaxies at high redshift have been found to be considerably more compact than galaxies of similar mass in the local universe. How these compact galaxies formed has yet to be determined, though several progenitor…
The traditional view of elliptical galaxies has been that they formed in a single, rapid burst of star formation at high redshift, and have evolved quiescently since that time. In opposition to this traditional view is evidence that at…
Majority of all galaxies reside in groups of less than 50 member galaxies. These groups are distributed in various large-scale environments from voids to superclusters. Evolution of galaxies is affected by the environment in which they…