English

Time-Dependent AGN Disc Winds II -- Effects of Photoionization

High Energy Astrophysical Phenomena 2025-04-02 v1

Abstract

We use a combination of radiation hydrodynamics (rad-HD) and photoionization modeling to study line-driven disc winds for a range of black hole masses. We refined previous models by incorporating heating, cooling, and radiation forces from spectral lines calculated using a photoionization code, assuming that composite AGN spectra irradiate the gas. For black holes with masses 3×106MBH/M1083 \times 10^{6} \lesssim {\rm M_{BH}/M_{\odot}} \lesssim 10^{8}, the mass loss rate, M˙w{\rm \dot{M}_w} increases proportionally with the disk Eddington fraction, Γ\Gamma. The insensitivity of M˙w{\rm \dot{M}_w} to the hardness of the spectral energy distribution (SED) arises because the central region is dominated by radiation in the frequency range with ample spectral lines for the range of MBHM_{BH} considered here. Disc winds are suppressed or fail outside the above mass range because of a dearth of line-driving photons. We find \emph{stronger} winds, both in terms of M˙w{\rm \dot{M}_w} and wind velocity compared to previous disc wind models. Our winds are stronger because of an enhanced line force from including many spectral lines in the X-ray band. These lines were unavailable and, hence, unaccounted for in previous photoionization studies and their subsequent application to AGN wind models. For Γ0.4\Gamma \gtrsim 0.4, M˙w{\rm \dot{M}_w} is higher than the assumed disc accretion rate, implying that the wind feeds back strongly. Our findings indicate the necessity of utilizing comprehensive and current atomic data along with a more thorough approach to radiation transfer - both spatially and temporally - to accurately calculate the line force.

Keywords

Cite

@article{arxiv.2504.00117,
  title  = {Time-Dependent AGN Disc Winds II -- Effects of Photoionization},
  author = {Sergei Dyda and Randall C. Dannen and Timothy R. Kallman and Shane W. Davis and Daniel Proga},
  journal= {arXiv preprint arXiv:2504.00117},
  year   = {2025}
}

Comments

12 pages, 11 figures