2020/01/31 by Yong Tian, Keiichi Umetsu, Chung-Ming Ko +2 · 1 citation
Physics and Astronomy · #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/ab8e3d
published as The Astrophysical Journal, 896, 70 (2020) · Version accepted by ApJ. Textual changes to improve clarity. Semi-analytical model predictions improved (Figures 3, 4, and 5), better agreement with data. Results and conclusions unchanged
arxiv created 2020/04/27 · arxiv updated 2020/06/17
The radial acceleration relation (RAR) in galaxies describes a tight empirical scaling law between the total acceleration gtot(r)=GMtot(<r)/r2 observed in galaxies and that expected from their baryonic mass gbar(r)=GMbar(<r)/r2, with a characteristic acceleration scale of g_†≃ 1.2× 10-10ms-2. Here, we examine if such a correlation exists in galaxy clusters using weak-lensing, strong-lensing, and X-ray data sets available for 20 high-mass clusters targeted by the CLASH survey. By combining our CLASH data with stellar mass estimates for the brightest cluster galaxies (BCGs) and accounting for the stellar baryonic component in clusters, we determine, for the first time, an RAR on BCG--cluster scales. The resulting RAR is well described by a tight power-law relation, gtot∝ gbar^0.51+0.04-0.05, with lognormal intrinsic scatter of 14.7+2.9-2.8%. The slope is consistent with the low acceleration limit of the RAR in galaxies, gtot=√(g_† gbar), whereas the intercept implies a much higher acceleration scale of g_\ddagger = (2.02±0.11)× 10-9ms-2, indicating that there is no universal RAR that holds on all scales from galaxies to clusters. We find that the observed RAR in CLASH clusters is consistent with predictions from a semi-analytical model developed in the standard ΛCDM framework. Our results also predict the presence of a baryonic Faber--Jackson relation (σv4∝ Mbar) on cluster scales.