2024PASJ...76.1143M

We study the environmental effect of galaxy evolution as a function of the underlying three-dimensional dark matter density for the first time at $z=2$-2.5, in which the underlying matter density is reconstructed from observed galaxies through dynamical forward modeling techniques. Utilizing this map, we investigate the dependence of the star formation activities and galaxy types (mergers, submillimeter galaxies, active galactic nuclei, and quiescent galaxies) on the matter overdensity $\Delta _{\rm local}$ and stellar mass. For the first time, we are able to probe underdense regions ($\Delta _{\rm local}\\lt 1$) in addition to overdensities. We find that star formation activity generally depends on the stellar mass, not the matter density. We also find evidence that there is an absence of mergers and submillimeter galaxies in higher-density regions but otherwise no trend across lower-density bins, and that there is an increase in the prevalence of active galactic nuclei and quiescent galaxies as a function of matter density, and an increase of all aforementioned categories with stellar mass. These results indicate that stellar mass is the main driver of galaxy evolution at the cosmic noon. Our novel approach directly using reconstructed dark matter density maps demonstrates the new capability of studies of the environmental effect of galaxy evolution at higher redshift.