The role of radiation pressure in the narrrow line regions of Seyfert host galaxies

Date

2016-06-10

Authors

Dopita, Michael A.
Kewley, Lisa
Groves, Brent
Sutherland, Ralph
Hampton, Elise J.
Shastri, Prajval
Kharb, Preeti
Bhatt, Harish
Scharwächter, Julia
Jin, Chichuan

Journal Title

Journal ISSN

Volume Title

Publisher

American Astronomical Society

Abstract

We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-active galactic nucleus (AGN) mixing curves on standard emission line diagnostic diagrams, which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ∼ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ∼ 0 to −3.2 ≤ log U ≤ −3.4. Where radiation pressure is dominant, the AGN regulates the density of the interstellar medium on kiloparsec scales and may therefore have a direct impact on star formation activity and/or the incidence of outflows in the host galaxy to scales far beyond the zone of influence of the black hole. We find that both radiation pressure dominated and gas pressure dominated ENLRs are dynamically active with evidence for outflows, indicating that radiation pressure may be an important source of AGN feedback even when it is not dominant over the entire ENLR.

Description

Keywords

galaxies, active, ISM, Seyfert

Citation

Source

The Astrophysical Journal

Type

Journal article

Book Title

Entity type

Access Statement

Open Access

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