Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-02-08
Mon.Not.Roy.Astron.Soc.369:1698-1702,2006
Astronomy and Astrophysics
Astrophysics
5 pages, 3 figures, Accepted for publication in MNRAS(Letters)
Scientific paper
10.1111/j.1365-2966.2006.10421.x
We employ a high-resolution dissipationless N-body simulation of a galaxy cluster to investigate the impact of subhalo selection on the resulting velocity distributions. Applying a lower limit on the present bound mass of subhalos leads to high subhalo velocity dispersions compared to the diffuse dark matter (positive velocity bias) and to a considerable deviation from a Gaussian velocity distribution (kurtosis -0.6). However, if subhalos are required to exceed a minimal mass before accretion onto the host, the velocity bias becomes negligible and the velocity distribution is close to Gaussian (kurtosis -0.15). Recently it has been shown that the latter criterion results in subhalo samples that agree well with the observed number-density profiles of galaxies in clusters. Therefore we argue that the velocity distributions of galaxies in clusters are essentially un-biased. The comparison of the galaxy velocity distribution and the sound speed, derived from scaling relations of X-ray observations, results in an average Mach number of 1.24. Altogether 65% of the galaxies move supersonically and 8% have Mach numbers larger than 2 with respect to the intra cluster gas.
Diemand Jürg
Faltenbacher Aandreas
No associations
LandOfFree
Velocity distributions in clusters of 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 Velocity distributions in clusters of galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Velocity distributions in clusters of galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-567582