A Self-Consistent Treatment of the Line-Driving Radiation Force for Active Galactic Nuclei Outflows: New Prescriptions for Simulations

Fuente: arXiv
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Main Authors: Lattimer, Aylecia S., Cranmer, Steven R.
Format: Preprint
Published: 2024
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author Lattimer, Aylecia S.
Cranmer, Steven R.
author_facet Lattimer, Aylecia S.
Cranmer, Steven R.
contents Flows driven by photons have been studied for almost a century, and a quantitative description of the radiative forces on atoms and ions is important for understanding a wide variety of systems with outflows and accretion disks, such as active galactic nuclei. Quantifying the associated forces is crucial to determining how these outflows enable interactive mechanisms within these environments, such as AGN feedback. The total number of spectral lines in any given ion of the outflow material must be tabulated in order to give a complete characterization of this force. Here we provide calculations of the dimensionless line force multiplier for AGN environments. For a wide array of representative AGN sources, we explicitly calculate the photoionization balance at the proposed wind-launching region above the accretion disk, compute the strength of the line-driving force on the gas, and revisit and formalize the role of the commonly-used ionization parameter $ξ$ in ultimately determining the line-driving force. We perform these computations and analyses for a variety of AGN central source properties, such as black hole mass, initial wind velocity, and number density. We find that, while useful, the ionization parameter provides an incomplete description of the overall ionization state of the outflow material. We use these findings to provide an updated method for calculating the strength of the radiative line-driving using both the X-ray spectral index $Γ_X$ and the ionization parameter.
format Preprint
id arxiv_https___arxiv_org_abs_2404_11926
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Self-Consistent Treatment of the Line-Driving Radiation Force for Active Galactic Nuclei Outflows: New Prescriptions for Simulations
Lattimer, Aylecia S.
Cranmer, Steven R.
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
Flows driven by photons have been studied for almost a century, and a quantitative description of the radiative forces on atoms and ions is important for understanding a wide variety of systems with outflows and accretion disks, such as active galactic nuclei. Quantifying the associated forces is crucial to determining how these outflows enable interactive mechanisms within these environments, such as AGN feedback. The total number of spectral lines in any given ion of the outflow material must be tabulated in order to give a complete characterization of this force. Here we provide calculations of the dimensionless line force multiplier for AGN environments. For a wide array of representative AGN sources, we explicitly calculate the photoionization balance at the proposed wind-launching region above the accretion disk, compute the strength of the line-driving force on the gas, and revisit and formalize the role of the commonly-used ionization parameter $ξ$ in ultimately determining the line-driving force. We perform these computations and analyses for a variety of AGN central source properties, such as black hole mass, initial wind velocity, and number density. We find that, while useful, the ionization parameter provides an incomplete description of the overall ionization state of the outflow material. We use these findings to provide an updated method for calculating the strength of the radiative line-driving using both the X-ray spectral index $Γ_X$ and the ionization parameter.
title A Self-Consistent Treatment of the Line-Driving Radiation Force for Active Galactic Nuclei Outflows: New Prescriptions for Simulations
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2404.11926