Does black-hole growth depend on the cosmic environment?. Issue 1 (19th July 2018) - Yang(杨光), G
ABSTRACT: It is well known that environment affects galaxy evolution, which is broadly related to supermassive black hole (SMBH) growth. We investigate whether SMBH evolution also depends on host-galaxy local (sub-Mpc) and global (≈1–10 Mpc) environment. We construct the surface-density field (local environment) and cosmic web (global environment) in the Cosmic Evolution Survey (COSMOS) field at $z$ = 0.3–3.0. The environments in COSMOS range from the field to clusters ( M halo ≲ 10 14 M⊙ ), covering the environments where ${\approx\!99{{\ \rm per\ cent}}}$ of galaxies in the Universe reside. We measure sample-averaged SMBH accretion rate ($\overline{\rm BHAR}$ ) from X-ray observations, and study its dependence on overdensity and cosmic-web environment at different redshifts while controlling for galaxy stellar mass ( M ⋆ ). Our results show that $\overline{\rm BHAR}$ does not significantly depend on overdensity or cosmic-web environment once M ⋆ is controlled, indicating that environment-related physical mechanisms (e.g. tidal interaction and ram-pressure stripping) might not significantly affect SMBH growth. We find that $\overline{\rm BHAR}$ is strongly related to host-galaxy M ⋆, regardless of environment.