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The star formation and AGN luminosity relation: predictions from a semi-analytical model

Gutcke, T.A.; Fanidakis, N.; Macciò, A.V.; Lacey, C.G.

The star formation and AGN luminosity relation: predictions from a semi-analytical model Thumbnail


T.A. Gutcke

N. Fanidakis

A.V. Macciò


In a universe where active galactic nucleus (AGN) feedback regulates star formation in massive galaxies, a strong correlation between these two quantities is expected. If the gas causing star formation is also responsible for feeding the central black hole, then a positive correlation is expected. If powerful AGNs are responsible for the star formation quenching, then a negative correlation is expected. Observations so far have mainly found a mild correlation or no correlation at all [i.e. a flat relation between star formation rate (SFR) and AGN luminosity], raising questions about the whole paradigm of ‘AGN feedback’. In this paper, we report the predictions of the GALFORM GALFORM semi-analytical model, which has a very strong coupling between AGN activity and quenching of star formation. The predicted SFR–AGN luminosity correlation appears negative in the low AGN luminosity regime, where AGN feedback acts, but becomes strongly positive in the regime of the brightest AGN. Our predictions reproduce reasonably well recent observations by Rosario et al., yet there is some discrepancy in the normalization of the correlation at low luminosities and high redshifts. Though this regime could be strongly influenced by observational biases, we argue that the disagreement could be ascribed to the fact that GALFORM GALFORM neglects AGN variability effects. Interestingly, the galaxies that dominate the regime where the observations imply a weak correlation are massive early-type galaxies that are subject to AGN feedback. Nevertheless, these galaxies retain high enough molecular hydrogen contents to maintain relatively high SFRs and strong infrared emission.


Gutcke, T., Fanidakis, N., Macciò, A., & Lacey, C. (2015). The star formation and AGN luminosity relation: predictions from a semi-analytical model. Monthly Notices of the Royal Astronomical Society, 451(4), 3759-3767.

Journal Article Type Article
Acceptance Date May 23, 2015
Publication Date Aug 21, 2015
Deposit Date Nov 30, 2015
Publicly Available Date Feb 11, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 451
Issue 4
Pages 3759-3767
Keywords Galaxies: active, Galaxies: evolution, Galaxies: general, Quasars: general, Galaxies: starburst.


Published Journal Article (2.9 Mb)

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

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