Flux-Averaged Force Multipliers

TL;DR

This paper introduces a flux-averaged force multiplier method for simulating line-driven AGN winds across multiple frequency bands, revealing significant contributions from non-UV bands that enhance wind properties.

Contribution

It presents a novel multi-frequency radiation hydrodynamics approach that improves upon grey models by incorporating frequency-dependent effects in line-driven wind simulations.

Findings

Non-negligible contributions from optical and X-ray bands enhance wind mass flux and velocity.

Frequency-dependent modeling captures effects missed by grey approaches.

Results support the importance of multi-frequency studies in radiation-driven wind dynamics.

Abstract

We apply novel developments in photoionization modeling and multi-frequency radiation hydrodynamics to the study of line driven AGN disc winds. We use a flux-averaged force multiplier approach to compute the radiation force due to lines for hydrodynamics simulations using 4 frequency bands - infrared (IR), optical (O), ultraviolet (UV) and X-rays. Though line driving is dominated by the UV, contributions from the O and X-ray bands are non-negligible and can lead to enhancements in the wind both in terms of mass flux and outflow velocity. Crucially, these effects are not captured when using a ``grey'' approach to the radiation modeling in the hydrodynamics, where frequency information is averaged over during the photoionization modeling. These results further strengthen the case for frequency dependent radiation dynamics studies for line driven winds.