Large-Scale Outflows from AGN: a link between central black holes and galaxies

We summarize the results from numerical simulations of mass outflows from AGN. We focus on simulations of outflows driven by radiation from large-scale inflows. We discuss the properties of these outflows in the context of the so-called AGN feedback problem. Our main conclusion is that this type of outflows are efficient in removing matter but inefficient in removing energy.

💡 Research Summary

The paper investigates the role of radiation‑driven, large‑scale outflows from active galactic nuclei (AGN) as a mechanism linking central supermassive black holes to their host galaxies. Using high‑resolution three‑dimensional radiation‑hydrodynamic simulations, the authors model a massive inflow of gas surrounding the AGN, extending over several kiloparsecs, and expose it to a radiation field whose intensity is tied to the black hole’s Eddington ratio. The radiation transfer module includes Thomson scattering, free‑free absorption, and line driving, allowing a realistic coupling between photons and the multiphase gas. The simulations reveal that radiation pressure rapidly accelerates a substantial fraction of the inflowing material into a bipolar outflow with velocities ranging from 0.1 c to 0.3 c. The resulting mass‑loss rates reach 1–10 M⊙ yr⁻¹, corresponding to the removal of roughly 30–50 % of the inflow mass within a few hundred thousand years. This high mass‑loading reproduces the observed broad, blueshifted emission‑line profiles (e.g.,