ALMA and Herschel reveal that X-ray-selected AGN and main-sequence galaxies have different star formation rate distributions

Mullaney, J.R.; Alexander, D.M.; Aird, J.; Bernhard, E.; Daddi, E.; Del Moro, A.; Dickinson, M.; Elbaz, D.; Harrison, C.M.; Juneau, S.; Liu, D.; Pannella, M.; Rosario, D.; Santini, P.; Sargent, M.; Schreiber, C.; Simpson, J.; Stanley, F.

doi:10.1093/mnrasl/slv110

ALMA and Herschel reveal that X-ray-selected AGN and main-sequence galaxies have different star formation rate distributions

Mullaney, J.R.; Alexander, D.M.; Aird, J.; Bernhard, E.; Daddi, E.; Del Moro, A.; Dickinson, M.; Elbaz, D.; Harrison, C.M.; Juneau, S.; Liu, D.; Pannella, M.; Rosario, D.; Santini, P.; Sargent, M.; Schreiber, C.; Simpson, J.; Stanley, F.

Authors

J.R. Mullaney

Professor David Alexander d.m.alexander@durham.ac.uk
Professor

J. Aird

E. Bernhard

E. Daddi

A. Del Moro

M. Dickinson

D. Elbaz

C.M. Harrison

S. Juneau

D. Liu

M. Pannella

D. Rosario

P. Santini

M. Sargent

C. Schreiber

J. Simpson

F. Stanley

Abstract

Using deep Herschel and ALMA observations, we investigate the star formation rate (SFR) distributions of X-ray-selected active galactic nucleus (AGN) host galaxies at 0.5 < z < 1.5 and 1.5 < z < 4, comparing them to that of normal, star-forming (i.e. ‘main-sequence’, or MS) galaxies. We find that 34–55 per cent of AGNs in our sample have SFRs at least a factor of 2 below that of the average MS galaxy, compared to ≈15 per cent of all MS galaxies, suggesting significantly different SFR distributions. Indeed, when both are modelled as lognormal distributions, the mass and redshift-normalized SFR distributions of X-ray AGNs are roughly twice as broad, and peak ≈0.4 dex lower, than that of MS galaxies. However, like MS galaxies, the normalized SFR distribution of AGNs in our sample appears not to evolve with redshift. Despite X-ray AGNs and MS galaxies having different SFR distributions, the linear-mean SFR of AGNs derived from our distributions is remarkably consistent with that of MS galaxies, and thus with previous results derived from stacked Herschel data. This apparent contradiction is due to the linear-mean SFR being biased by bright outliers, and thus does not necessarily represent a true characterization of the typical SFR of X-ray AGNs.

Citation

Mullaney, J., Alexander, D., Aird, J., Bernhard, E., Daddi, E., Del Moro, A., …Stanley, F. (2015). ALMA and Herschel reveal that X-ray-selected AGN and main-sequence galaxies have different star formation rate distributions. Monthly Notices of the Royal Astronomical Society: Letters, 453(1), L83-L87. https://doi.org/10.1093/mnrasl/slv110

Journal Article Type	Article
Acceptance Date	Jul 29, 2015
Online Publication Date	Aug 25, 2015
Publication Date	Oct 11, 2015
Deposit Date	May 31, 2016
Publicly Available Date	Jun 15, 2016
Journal	Monthly Notices of the Royal Astronomical Society: Letters
Electronic ISSN	1745-3933
Publisher	Oxford University Press
Peer Reviewed	Peer Reviewed
Volume	453
Issue	1
Pages	L83-L87
DOI	https://doi.org/10.1093/mnrasl/slv110
Related Public URLs	http://adsabs.harvard.edu/abs/2015MNRAS.453L..83M

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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society: Letters ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.