Does concentration drive the scatter in the stellar-to-halo mass relation of galaxy clusters?. Issue 4 (17th June 2021)

• Record Type: Journal Article
• Authors: Zu, Ying; Shan, Huanyuan; Zhang, Jun; Singh, Sukhdeep; Shao, Zhiwei; Chen, Xiaokai; Yao, Ji; Golden-Marx, Jesse B; Cui, Weiguang; Jullo, Eric; Kneib, Jean-Paul; Zhang, Pengjie; Yang, Xiaohu
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 505:Issue 4(2021)
• Page Start: 5117
• Page End: 5128
• Publication Date: 2021-06-17
• Subjects: gravitational lensing: weak -- galaxies: formation -- large-scale structure of Universe; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab1712
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Concentration is one of the key dark matter halo properties that could drive the scatter in the stellar-to-halo mass relation of massive clusters. We derive robust photometric stellar masses for a sample of brightest central galaxies (BCGs) in SDSS redmapper clusters at 0.17 < z < 0.3, and split the clusters into two equal-halo mass subsamples by their BCG stellar mass $M_*^{\mathrm{BCG}}$ . The weak lensing profiles ΔΣ of the two cluster subsamples exhibit different slopes on scales below $1\, h^{-1}\, {\mathrm{Mpc}}$ . To interpret such discrepancy, we perform a comprehensive Bayesian modelling of the two ΔΣ profiles by including different levels of miscentring effects between the two subsamples as informed by X-ray observations. We find that the two subsamples have the same average halo mass of $1.74\times 10^{14}\, h^{-1}\, \mathrm{M}_{\odot }$, but the concentration of the low-$M_*^{\mathrm{BCG}}$ clusters is $5.87_{-0.60}^{+0.77}$, ∼1.5σ smaller than that of their high-$M_*^{\mathrm{BCG}}$ counterparts ($6.95_{-0.66}^{+0.78}$ ). Furthermore, both cluster weak lensing and cluster-galaxy cross-correlations indicate that the large-scale bias of the low-$M_*^{\mathrm{BCG}}$, low-concentration clusters are ${\sim}10{{\ \rm per\ cent}}$ higher than that of the high-$M_*^{\mathrm{BCG}}$, high-concentration systems, hence possible evidence of the cluster assembly bias effect. Our results reveal a remarkable physical connection between the stellar mass within $20{-}30\, h^{-1}\, {\mathrm{kpc}}$, the dark matter mass within ${\sim}200\, h^{-1}\, {\mathrm{kpc}}$, and the cosmic overdensity on scales above $10\, h^{-1}\, {\mathrm{Mpc}}$, enabling a key observational test of theories of co-evolution between massive clusters and their central galaxies.