Stellar and black hole assembly in z < 0.3 infrared-luminous mergers: intermittent starbursts versus super-Eddington accretion
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
We study stellar and black hole mass assembly in a sample of 42 infrared-luminous galaxy mergers at z < 0.3 by combining results from radiative transfer modelling with archival measures of molecular gas and black hole mass. The ratios of stellar mass, molecular gas mass, and black hole mass to each other are consistent with those of massive gas-rich galaxies at z < 0.3. The advanced mergers may show increased black hole mass to stellar mass ratios, consistent with the transition from active galactic nucleus (AGN) to ellipticals and implying substantial black hole mass growth over the course of the merger. Star formation rates are enhanced relative to the local main sequence, by factors of ∼100 in the starburst and ∼1.8 in the host, respectively. The starburst star formation rates appear distinct to star formation in the main sequence at all redshifts up to at least z ∼ 5. Starbursts may prefer late-stage mergers, but are observed at any merger stage. We do not find evidence that the starbursts in these low-redshift systems substantially increase the total stellar mass, with a soft upper limit on the stellar mass increase from starburst activity of about a factor of two. In contrast, 12 objects show evidence for super-Eddington accretion, associated with late-stage mergers, suggesting that many AGN in infrared-luminous mergers go through a super-Eddington phase. The super-Eddington phase may increase black hole mass by up to an order of magnitude at an accretion efficiency of 42 ± 33 per cent over a period of 44 ± 22 Myr. Our results imply that super-Eddington accretion is an important black hole growth channel in infrared-luminous galaxies at all redshifts.
Date Issued
2022-07-01
Date Acceptance
2022-03-21
Citation
Monthly Notices of the Royal Astronomical Society, 2022, 513 (4), pp.4770-4786
ISSN
0035-8711
Publisher
Oxford University Press
Start Page
4770
End Page
4786
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
513
Issue
4
Copyright Statement
© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This is a pre-copy-editing, author-produced version of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version Duncan Farrah, Andreas Efstathiou, Jose Afonso, Jeronimo Bernard-Salas, Joe Cairns, David L Clements, Kevin Croker, Evanthia Hatziminaoglou, Maya Joyce, Mark Lacy, Vianney Lebouteiller, Alix Lieblich, Carol Lonsdale, Seb Oliver, Chris Pearson, Sara Petty, Lura K Pitchford, Dimitra Rigopoulou, Michael Rowan-Robinson, Jack Runburg, Henrik Spoon, Aprajita Verma, Lingyu Wang, Stellar and black hole assembly in z < 0.3 infrared-luminous mergers: intermittent starbursts versus super-Eddington accretion, Monthly Notices of the Royal Astronomical Society, Volume 513, Issue 4, July 2022, Pages 4770–4786 is available online at: https://doi.org/10.1093/mnras/stac980
Subjects
ACTIVE GALACTIC NUCLEI
Astronomy & Astrophysics
BAND IMAGING SURVEY
galaxies: active
GALAXY MERGERS
LOCAL BASE-LINE
MASS SCALING RELATIONS
MOLECULAR GAS
Physical Sciences
quasars: general
Science & Technology
SPACE-TELESCOPE
SPECTRAL PROPERTIES
STAR-FORMATION RATES
X-RAY
Publication Status
Published
Date Publish Online
2022-04-15