Related papers: Early versus late type galaxies in compact groups
We present rotation curves for 19, mostly luminous, early-type disk galaxies. Rotation velocities are measured from a combination of HI velocity fields and long-slit optical emission line spectra along the major axis. We find that the…
We review the physical properties of nearby, relatively luminous galaxies, using results from newly available massive data sets together with more detailed observations. First, we present the global distribution of properties, including the…
I review recent and less recent work on globular cluster systems in early-type galaxies. Explaining their properties and possible assembly scenarios, touches on a variety of astrophysical topics from cluster formation itself to galaxy…
Elliptical galaxies formed in a major merger tend to become more nearly spherical with time, thanks to the gravitational effect of their central black hole (or black holes). Observational results indicate that elliptical galaxies with older…
We determine the age of 1,104 early-type galaxies in eight rich clusters ($z = 0.0046$ to $0.175$) using a new continuum color technique. We find that galaxies in clusters divide into two populations, an old population with a mean age…
Using cosmological N-body simulations of critical (SCDM) and open (Omega_0=0.3, OCDM) cold dark matter models we have identified dark matter halos which are associated with the progenitors of present day bright early type galaxies. By…
Young, massive star clusters are the most notable and significant end products of violent star-forming episodes triggered by galaxy collisions, mergers, and close encounters. Their contribution to the total luminosity induced by such…
Color gradients in early-type galaxies contain valuable clues about their formation and evolutionary histories and mechanisms. We examine color gradients in 1,700 early-type galaxies in 159 galaxy clusters spanning a redshift range of 0.05…
We present here the first study of the X-ray properties of an evolutionary sample of merging galaxies. Both ROSAT PSPC and HRI data are presented for a sample of eight interacting galaxy systems, each believed to involve a similar encounter…
We outline the results of a two-dimensional (2D) fit of the light distribution of early-type galaxies belonging to a complete volume-limited sample, and briefly discuss the significant correlations among the structural parameters. In…
In this paper I focus on three topics related to the dynamical evolution of small galaxy groups, for which the input of N-body simulations has been decisive. These are the merging rates in compact groups, the properties of remnants of…
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…
We study the formation and evolution of small groups of galaxies using new Monte Carlo simulations. These are directly based on the random walk approach to the statistics of condensations collapsing by gravitational instability, and the…
We analyse the phase-space structure of simulated thick discs that are the result of a significant merger between a disc galaxy and a satellite. Our main goal is to establish what would be the characteristic imprints of a merger origin for…
Numerical simulations as well as optical and X-ray observations over the last few years have shown that poor groups of galaxies can evolve to what is called a fossil group. Dynamical friction as the driving process leads to the coalescence…
Compact groups of galaxies are devised as extreme environments where interactions may drive galaxy evolution. In this work, we analysed whether the luminosities of galaxies inhabiting compact groups differ from those of galaxies in loose…
We discuss evidence in local, present-day clusters of galaxies (from the ENACS survey) about the way in which those clusters have evolved and about the evolutionary relationships between the galaxies of different morphological types in…
We calculated the median values of the following parameters for 87 groups of galaxies with three to eight components: the mean rms velocity of the galaxies in the group, S_v = 166 km/s; the harmonic mean radius, R_h = 29 kpc; and the…
Theoretical considerations and observational data support the idea that mergers were more frequent in the past. At redshifts z = 2 to 5, violent interactions and mergers may be implicated by observations of Lyman-break galaxies, sub-mm…
Isolated galaxies in low-density regions are significant in the sense that they are least affected by the hierarchical pattern of galaxy growth, and interactions with perturbers, at least for the last few Gyr. To form a comprehensive…