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Durham University

Department of Physics

Staff profile

Publication details for Prof David Alexander

Yang(杨光), G., Brandt, W. N., Darvish, B., Chen(陳建廷), C.-T. J., Vito, F., Alexander, D. M., Bauer, F. E. & Trump, J. R. (2018). Does black-hole growth depend on the cosmic environment? Monthly Notices of the Royal Astronomical Society 480(1): 1022-1042.

Author(s) from Durham


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

= 0.3–3.0. The environments in COSMOS range from the field to clusters (Mhalo ≲ 1014 M⊙), covering the environments where
≈99 per cent

of galaxies in the Universe reside. We measure sample-averaged SMBH accretion rate (

) 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

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

is strongly related to host-galaxy M⋆, regardless of environment.