Do satellite galaxies trace matter in galaxy clusters?

TL;DR

This study compares the spatial distribution of satellite galaxies with the underlying matter distribution in galaxy clusters, finding they follow similar NFW profiles and scale radii within uncertainties, using SDSS and CS82 data.

Contribution

It provides the first direct comparison of satellite galaxy density profiles with total matter profiles in galaxy clusters using weak lensing data.

Findings

Mass and galaxy density profiles are both well fitted by NFW profiles.

The scale radii of mass and galaxy distributions agree within 1σ.

Satellite galaxies trace the underlying matter distribution in clusters.

Abstract

The spatial distribution of satellite galaxies encodes rich information of the structure and assembly history of galaxy clusters. In this paper, we select a redMaPPer cluster sample in SDSS Stripe 82 region with $0.1 \le z \le 0.33$, $20<\lambda<100$ and $P_{\rm cen}>0.7$. Using the high-quality weak lensing data from CS82 Survey, we constrain the mass profile of this sample. Then we compare directly the mass density profile with the satellite number density profile. We find that the total mass and number density profiles have the same shape, both well fitted by an NFW profile. The scale radii agree with each other within 1$\sigma$ error ($r_{\rm s,gal}=0.34_{-0.03}^{+0.04}$Mpc vs $r_{\rm s}=0.37_{-0.10}^{+0.15}$Mpc ).