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The Star-Formation Properties of the Observed and Simulated AGN Universe: BAT vs EAGLE

Jackson, Thomas M.; Rosario, D.J.; Alexander, D.M.; Scholtz, J.; McAlpine, Stuart; Bower, R.G.

The Star-Formation Properties of the Observed and Simulated AGN Universe: BAT vs EAGLE Thumbnail


Thomas M. Jackson

D.J. Rosario

J. Scholtz

Stuart McAlpine

R.G. Bower


In this paper we present data from 72 low redshift, hard X-ray selected AGN taken from the Swift-BAT 58 month catalogue. We utilise spectral energy distribution fitting to the optical to IR photometry in order to estimate host galaxy properties. We compare this observational sample to a volume and flux matched sample of AGN from the EAGLE hydrodynamical simulations in order to verify how accurately the simulations can reproduce observed AGN host galaxy properties. After correcting for the known +0.2 dex offset in the SFRs between EAGLE and previous observations, we find agreement in the SFR and X-ray luminosity distributions; however we find that the stellar masses in EAGLE are 0.2 − 0.4 dex greater than the observational sample, which consequently leads to lower sSFRs. We compare these results to our previous study at high redshift, finding agreement in both the observations and simulations, whereby the widths of sSFR distributions are similar (∼0.4 − 0.6 dex) and the median of the SFR distributions lie below the star forming main sequence by ∼0.3 − 0.5 dex across all samples. We also use EAGLE to select a sample of AGN host galaxies at high and low redshift and follow their characteristic evolution from z = 8 to z = 0. We find similar behaviour between these two samples, whereby star formation is quenched when the black hole goes through its phase of most rapid growth. Utilising EAGLE we find that 23% of AGN selected at z ∼ 0 are also AGN at high redshift, and that their host galaxies are among the most massive objects in the simulation. Overall we find EAGLE reproduces the observations well, with some minor inconsistencies (∼ 0.2 dex in stellar masses and ∼ 0.4 dex in sSFRs).


Jackson, T. M., Rosario, D., Alexander, D., Scholtz, J., McAlpine, S., & Bower, R. (2020). The Star-Formation Properties of the Observed and Simulated AGN Universe: BAT vs EAGLE. Monthly Notices of the Royal Astronomical Society, 498(2), 2323-2338.

Journal Article Type Article
Acceptance Date Aug 11, 2020
Online Publication Date Sep 2, 2020
Publication Date 2020-10
Deposit Date Sep 3, 2020
Publicly Available Date Oct 6, 2020
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 498
Issue 2
Pages 2323-2338
Public URL


Published Journal Article (960 Kb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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