The Outer Stellar Mass of Massive Galaxies: A Simple Tracer of Halo Mass with Scatter Comparable to Richness and Reduced Projection Effects

Understand

Using the weak gravitational lensing data from the Hyper Suprime-Cam Subaru Strategic Program (HSC survey), we study the potential of different stellar mass estimates in tracing halo mass.

• We consider galaxies with $\log {M_{\star}/M_{\odot}}>11.5$ at 0.2 < z < 0.5 with carefully measured light profiles and clusters from the redMaPPer and CAMIRA richness-based algorithms.
• We devise a method (the &#34;TopN&#34; test) to evaluate the scatter in the halo mass-observable relation for different tracers and inter-compare halo mass proxies in four number density bins using stacked galaxy-galaxy lensing profiles.
• This test reveals three key findings.