Title: Utilizing the Stellar Halo of Massive Galaxies for Cluster Cosmology

Speaker:Song Huang  (Tsinghua)

Time: Thursday, 3:00pm, Apr 7th

Tencent Meeting:255-373-453

Abstract: The abundance and lensing signals of massive galaxy clusters contain valuable information about the underlying cosmology model. Although cluster cosmology has excellent potential in the near future, identifying clusters and the measurements of their halo mass are still very challenging tasks. Taking advantage of the high-quality deep images from the Subaru HSC survey and its unprecedented galaxy-galaxy lensing capability, we revisit the possibility of using massive central galaxy to find galaxy clusters and measure halo mass. And we propose straightforward tests to compare central galaxy-based cluster finder with the popular richness-based finder with the help of cosmological simulation. These tests demonstrate that a massive galaxy's outer stellar halo is a good proxy of halo mass and tracer of recent halo assembly. I will discuss the cosmological implication of these results along with the future perspective with the help from DESI and MUST - the 6.5-meter spectroscopic survey telescope led by Tsinghua University.