Shallow Dark Matter Cusps in Galaxy Clusters

Abstract

We study the evolution of the stellar and dark matter components in a galaxy cluster of $10^{15}{\mathrm{M}}_{\odot }$ from $z=3$ to the present epoch using the high-resolution collisionless simulations of Ruszkowski & Springel (2009). At $z=3$ the dominant progenitor halos were populated with spherical model galaxies with and without accounting for adiabatic contraction. We apply a weighting scheme which allows us to change the relative amount of dark and stellar material assigned to each simulation particle in order to produce luminous properties which agree better with abundance matching arguments and observed bulge sizes at $z=3$. This permits the study of the effect of initial compactness on the evolution of the mass-size relation. We find that for more compact initial stellar distributions the size of the final Brightest Cluster Galaxy grows with mass according to $r\propto M^2$, whereas for more extended initial distributions, $r\propto M$. Our results show that collisionless mergers in a cosmological context can reduce the strength of inner dark matter cusps with changes in logarithmic slope of 0.3 to 0.5 at fixed radius. Shallow cusps such as those found recently in several strong lensing clusters thus do not necessarily conflict with CDM, but may rather reflect on the initial structure of the progenitor galaxies, which was shaped at high redshift by their formation process.

8 pages, 4 figures, submitted to MNRAS

References in corpus (5)

• The hierarchical formation of the brightest cluster galaxies
• How special are Brightest Group and Cluster Galaxies?
• The luminosities, sizes and velocity dispersions of Brightest Cluster Galaxies: Implications for formation history
• The effects of baryon physics, black holes and AGN feedback on the mass distribution in clusters of galaxies
• Separating baryons and dark matter in cluster cores: a full 2-D lensing and dynamic analysis of Abell 383 and MS2137-23

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