Does black-hole growth depend on the cosmic environment?
  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 ($\approx
1-10$ Mpc) environment. We construct the surface-density field (local
environment) and cosmic web (global environment) in the COSMOS field at
$z=0.3-3.0$. The environments in COSMOS range from the field to clusters
($M_\mathrm{halo} \lesssim 10^{14}\ M_\odot$), covering the environments where
${\approx 99\%}$ of galaxies in the Universe reside. We measure sample-averaged
SMBH accretion rate ($\overline{\mathrm{BHAR}}$) from X-ray observations, and
study its dependence on overdensity and cosmic-web environment at different
redshifts while controlling for galaxy stellar mass ($M_\star$). Our results
show that $\overline{\mathrm{BHAR}}$ does not significantly depend on
overdensity or cosmic-web environment once $M_\star$ 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 $\overline{\mathrm{BHAR}}$ is strongly related to host-galaxy $M_\star$,
regardless of environment.
