Speaker
Description
We use a 500 cluster sample from the HectoMAP redshift survey combined with the IllustrisTNG 300-1 simulation to explore the evolution of cluster members and their host clusters. We use the central stellar velocity dispersions, a fundamental observable that links galaxies with their dark matter subhalos. For a fair comparison with observed stellar velocity dispersions, we carefully examine the central velocity dispersion measurements for subhalos in IllustrisTNG-300. Based on the observed and simulated velocity dispersions, we explore the co-evolution of the brightest cluster galaxies (BCGs) and clusters based on their dynamical scaling relations. The observed ratio between the BCG velocity dispersion and cluster velocity dispersion declines as a function of cluster velocity dispersion for redshift $z < 0.6$, indicating that the BCG mass fraction decreases as a function of cluster mass. The simulated relation is consistent with the observed relation with a larger scatter. We also investigate the redshift evolution of the dynamical scaling relation, which can be a direct test for the structure formation model. These predictions that probe the evolution of the most massive galaxies and their host structures are useful tests for JWST and dense, deep future spectroscopic surveys.
