Using the outskirts of galaxy clusters to determine their mass accretion rate [CEA]

http://arxiv.org/abs/1612.03909


We explore the possibility of using the external regions of galaxy clusters to measure their mass accretion rate (MAR). The main goal is to provide a method to observationally investigate the growth of structures on the nonlinear scales of galaxy clusters. We derive the MAR by using the mass profile beyond the splashback radius, evaluating the mass of a spherical shell and the time it takes to fall in. The infall velocity of the shell is extracted from $N$-body simulations. The average MAR returned by our prescription in the redshift range $z=[0, 2]$ is within $20-40 \%$ of the average MAR derived from the merger trees of dark matter haloes in the reference $N$-body simulations. Our result suggests that the external regions of galaxy clusters can be used to measure the mean MAR of a sample of clusters.

Read this paper on arXiv…

C. Boni
Wed, 14 Dec 16
57/67

Comments: 7 pages, 2 figures, based on arXiv:1501.01977 and on a short poster presentation at EWASS 2016, accepted for publication in “Galaxies”, Special Issue for the EWASS 2016 Symposium, “Exploring the outskirts of galaxy clusters”, Athens 4-5 July 2016