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A unified multiwavelength model of galaxy formation

Lacey, Cedric G.; Baugh, Carlton M.; Frenk, Carlos S.; Benson, Andrew J.; Bower, Richard G.; Cole, Shaun; Gonzalez-Perez, Violeta; Helly, John C.; Lagos, Claudia D.P.; Mitchell, Peter D.

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Carlos S. Frenk

Andrew J. Benson

Richard G. Bower

Shaun Cole

Violeta Gonzalez-Perez

Claudia D.P. Lagos

Peter D. Mitchell


We present a new version of the GALFORM semi-analytical model of galaxy formation. This brings together several previous developments of GALFORM into a single unified model, including a different initial mass function (IMF) in quiescent star formation and in starbursts, feedback from active galactic nuclei supressing gas cooling in massive halos, and a new empirical star formation law in galaxy disks based on their molecular gas content. In addition, we have updated the cosmology, introduced a more accurate treatment of dynamical friction acting on satellite galaxies, and updated the stellar population model. The new model is able to simultaneously explain both the observed evolution of the K-band luminosity function and stellar mass function, and the number counts and redshift distribution of sub-mm galaxies selected at 850μm. This was not previously achieved by a single physical model within the ΛCDM framework, but requires having an IMF in starbursts that is somewhat top-heavy. The new model is tested against a wide variety of observational data covering wavelengths from the far-UV to sub-mm, and redshifts from z = 0 to z = 6, and is found to be generally successful. These observations include the optical and near-IR luminosity functions, HI mass function, fraction of early type galaxies, Tully-Fisher, metallicity-luminosity and size-luminosity relations at z = 0, as well as far-IR number counts, and far-UV luminosity functions at z ∼ 3 − 6. Discrepancies are however found in galaxy sizes and metallicities at low luminosities, and in the abundance of low mass galaxies at high-z, suggesting the need for a more sophisticated model of supernova feedback.


Lacey, C. G., Baugh, C. M., Frenk, C. S., Benson, A. J., Bower, R. G., Cole, S., …Mitchell, P. D. (2016). A unified multiwavelength model of galaxy formation. Monthly Notices of the Royal Astronomical Society, 462(4), 3854-3911.

Journal Article Type Article
Acceptance Date Jul 28, 2016
Online Publication Date Aug 1, 2016
Publication Date Nov 11, 2016
Deposit Date Aug 18, 2016
Publicly Available Date Aug 19, 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 462
Issue 4
Pages 3854-3911


Accepted Journal Article (3.6 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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