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Galaxy and Mass Assembly (GAMA): The Weak Environmental Dependence of Quasar Activity at 0.1< z <0.35

Wethers, Clare F; Acharya, Nischal; De Propris, Roberto; Kotilainen, Jari; Baldry, Ivan K; Brough, Sarah; Driver, Simon P; Graham, Alister W; Holwerda, Benne W; Hopkins, Andrew M; López-Sánchez, Angel R; Loveday, Jonathan; Phillipps, Steven; Pimbblet, Kevin A.; Taylor, Edward; Wang, Lingyu; Wright, Angus H


Clare F Wethers

Nischal Acharya

Roberto De Propris

Jari Kotilainen

Ivan K Baldry

Sarah Brough

Simon P Driver

Alister W Graham

Benne W Holwerda

Andrew M Hopkins

Angel R López-Sánchez

Jonathan Loveday

Steven Phillipps

Edward Taylor

Lingyu Wang

Angus H Wright


Understanding the connection between nuclear activity and galaxy environment remains critical in constraining models of galaxy evolution. By exploiting extensive catalogued data from the Galaxy and Mass Assembly (GAMA) survey, we identify a representative sample of 205 quasars at 0.1 < z < 0.35 and establish a comparison sample of galaxies, closely matched to the quasar sample in terms of both stellar mass and redshift. On scales <1 Mpc, the galaxy number counts and group membership of quasars appear entirely consistent with those of the matched galaxy sample. Despite this, we find that quasars are ?1.5 times more likely to be classified as the group center, indicating a potential link between quasar activity and cold gas flows or galaxy interactions associated with rich group environments. On scales of ?a few Mpc, the clustering strength of both samples are statistically consistent and beyond 10 Mpc we find no evidence that quasars trace large scale structures any more than the galaxy control sample. Both populations are found to prefer intermediate-density sheets and filaments to either very high-or very low-density environments. This weak dependence of quasar activity on galaxy environment supports a paradigm in which quasars represent a phase in the lifetime of all massive galaxies and in which secular processes and a group-centric location are the dominant trigger of quasars at low redshift.


Wethers, C. F., Acharya, N., De Propris, R., Kotilainen, J., Baldry, I. K., Brough, S., …Wright, A. H. (2022). Galaxy and Mass Assembly (GAMA): The Weak Environmental Dependence of Quasar Activity at 0.1< z

Journal Article Type Article
Acceptance Date Dec 6, 2021
Online Publication Date Apr 7, 2022
Publication Date Apr 1, 2022
Deposit Date Jan 11, 2022
Publicly Available Date Oct 27, 2022
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 928
Issue 2
Article Number 192
Keywords Quasars; Galaxy evolution; Active galaxies
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Copyright Statement
© 2022. The Author(s). Published by the American Astronomical Society.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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