The peculiar velocity function of galaxy clusters

Feb, 1996
18 pages
Published in:
  • Astrophys.J.Lett. 462 (1996) L49
e-Print:
Report number:
  • POPE-658

Citations per year

1996200320102017202402468
Abstract: (arXiv)
The peculiar velocity function of clusters of galaxies is determined using an accurate sample of cluster velocities based on Tully-Fisher distances of Sc galaxies (Giovanelli et al 1995b). In contrast with previous results based on samples with considerably larger velocity uncertainties, the observed velocity function does not exhibit a tail of high velocity clusters. The results indicate a low probability of \lesssim\,5\% of finding clusters with one-dimensional velocities greater than \sim 600 {\kms}. The root-mean-square one-dimensional cluster velocity is 293±\pm28 {\kms}. The observed cluster velocity function is compared with expectations from different cosmological models. The absence of a high velocity tail in the observed function is most consistent with a low mass-density (Ω\Omega \sim0.3) CDM model, and is inconsistent at 3σ\gtrsim 3 \sigma level with Ω\Omega= 1.0 CDM and HDM models. The root-mean-square one-dimensional cluster velocities in these models correspond, respectively, to 314, 516, and 632 {\kms} (when convolved with the observational uncertainties). Comparison with the observed RMS cluster velocity of 293±\pm28 {\kms} further supports the low-density CDM model.