Pierce, J.C.S. orcid.org/0000-0002-8250-9083, Tadhunter, C., Ramos Almeida, C. et al. (8 more authors) (2023) Galaxy interactions are the dominant trigger for local type 2 quasars. Monthly Notices of the Royal Astronomical Society, 522 (2). pp. 1736-1751. ISSN 0035-8711
Abstract
The triggering mechanism for the most luminous, quasar-like active galactic nuclei (AGN) remains a source of debate, with some studies favouring triggering via galaxy mergers, but others finding little evidence to support this mechanism. Here, we present deep Isaac Newton Telescope/Wide Field Camera imaging observations of a complete sample of 48 optically selected type 2 quasars – the QSOFEED sample (L[O III] > 108.5 L; z < 0.14). Based on visual inspection by eight classifiers, we find clear evidence that galaxy interactions are the dominant triggering mechanism for quasar activity in the local universe, with 65+6−7 per cent of the type 2 quasar hosts showing morphological features consistent with galaxy mergers or encounters, compared with only 22+5−4 per cent of a stellar-mass- and redshift-matched comparison sample of non-AGN galaxies – a 5σ difference. The type 2 quasar hosts are a factor of 3.0+0.5 −0.8 more likely to be morphologically disturbed than their matched non-AGN counterparts, similar to our previous results for powerful 3CR radio AGN of comparable [O III] emission-line luminosity and redshift. In contrast to the idea that quasars are triggered at the peaks of galaxy mergers as the two nuclei coalesce, and only become visible post-coalescence, the majority of morphologically disturbed type 2 quasar sources in our sample are observed in the pre-coalescence phase (61+8−9 per cent). We argue that much of the apparent ambiguity that surrounds observational results in this field is a result of differences in the surface brightness depths of the observations, combined with the effects of cosmological surface brightness dimming.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
Keywords: | galaxies: active; galaxies: interactions; galaxies: nuclei |
Dates: |
|
Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Funding Information: | Funder Grant number SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/R000964/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 04 May 2023 12:26 |
Last Modified: | 04 May 2023 12:26 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Refereed: | Yes |
Identification Number: | 10.1093/mnras/stad455 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:198832 |