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arXiv · 1509.08473

A unified multi-wavelength model of galaxy formation

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

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 850 mu. This was not previously achieved by a single physical model within the LambdaCDM 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. [abridged]

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Cedric G. Lacey, Carlton M. Baugh, Carlos S. Frenk, Andrew J. Benson, Richard G. Bower, Shaun Cole, Violeta Gonzalez-Perez, John C. Helly, Claudia D. P. Lagos, Peter D. Mitchell. 2016-08-06. A unified multi-wavelength model of galaxy formation. https://doi.org/10.1093/mnras%2Fstw1888

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