Repository logo
 

AGN-starburst evolutionary connection: a physical interpretation based on radiative feedback

Published version
Peer-reviewed

Change log

Authors

Ishibashi, W 
Fabian, AC 

Abstract

Observations point towards a close connection between nuclear starbursts, active galactic nuclei (AGN), and outflow phenomena. An evolutionary sequence, starting from a dust-obscured ultra-luminous infrared galaxy and eventually leading to an unobscured optical quasar, has been proposed and discussed in the literature. AGN feedback is usually invoked to expel the obscuring gas and dust in a blow-out event, but the underlying physical mechanism remains unclear. We consider AGN feedback driven by radiation pressure on dust, which directly acts on the obscuring dusty gas. We obtain that radiative feedback can potentially disrupt dense gas in the infrared-optically thick regime, and that an increase in the dust-to-gas fraction leads to an increase in the effective Eddington ratio. Thus, the more dusty gas is preferentially expelled by radiative feedback, and the central AGN is prone to efficiently remove its own obscuring dust cocoon. Large amounts of dust imply heavy obscuration but also powerful feedback, suggesting a causal link between dust obscuration and blow-out. In this picture, AGN feedback and starburst phenomena are intrinsically coupled through the production of dust in supernova explosions, leading to a natural interpretation of the observed evolutionary path.

Description

Keywords

black hole physics, galaxies: active, galaxies: evolution, galaxies: starburst, infrared: galaxies

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

463

Publisher

Oxford University Press
Sponsorship
European Research Council (340442)
Science and Technology Facilities Council (ST/N000927/1)
WI acknowledges support from the Swiss National Science Foundation and ACF acknowledges support from ERC Advanced Grant 340442.