Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-11-07
Mon.Not.Roy.Astron.Soc.379:867-893,2007
Astronomy and Astrophysics
Astrophysics
Replaced with slightly modified version accepted by MNRAS. 28 pages, 25 figures. Version with full resolution figures availabl
Scientific paper
10.1111/j.1365-2966.2007.11940.x
We use the Sloan Digital Sky Survey to construct a sample of 625 brightest group and cluster galaxies (BCGs) together with control samples of non-BCGs matched in stellar mass, redshift, and color. We investigate how the systematic properties of BCGs depend on stellar mass and on their privileged location near the cluster center. The groups and clusters that we study are drawn from the C4 catalogue of Miller et al. (2005) but we have developed improved algorithms for identifying the BCG and for measuring the cluster velocity dispersion. Since the SDSS photometric pipeline tends to underestimate the luminosities of large galaxies in dense environments, we have developed a correction for this effect which can be readily applied to the published catalog data. We find that BCGs are larger and have higher velocity dispersions than non-BCGs of the same stellar mass, which implies that BCGs contain a larger fraction of dark matter. In contrast to non-BCGs, the dynamical mass-to-light ratio of BCGs does not vary as a function of galaxy luminosity. Hence BCGs lie on a different fundamental plane than ordinary elliptical galaxies. BCGs also follow a steeper Faber-Jackson relation than non-BCGs, as suggested by models in which BCGs assemble via dissipationless mergers along preferentially radial orbits. We find tentative evidence that this steepening is stronger in more massive clusters. BCGs have similar mean stellar ages and metallicities to non-BCGs of the same mass, but they have somewhat higher alpha/Fe ratios, indicating that star formation may have occurred over a shorter timescale in the BCGs. Finally, we find that BCGs are more likely to host radio-loud active galactic nuclei than other galaxies of the same mass, but are less likely to host an optical AGN. The differences we find are more pronounced for the less massive BCGs.
Best Philip N.
der Linden Anja von
Kauffmann Guinevere
White Simon D. M.
No associations
LandOfFree
How special are Brightest Group and Cluster Galaxies? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with How special are Brightest Group and Cluster Galaxies?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and How special are Brightest Group and Cluster Galaxies? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-616868