1509.08473
A unified multi-wavelength model of galaxy formation
Lacey, Baugh, Frenk, Benson, Bower, Cole, Gonzalez-Perez, Helly, Lagos, Mitchell
Present a new version of the GALFORM galaxy formation SAM. This brings together several previous developments of GALFORM into a single unified model, including a different IMF in quiescent SF and in starbursts, feedback from AGN suppressing gas cooling in massive haloes, and a new empirical SF law in galaxy disks based on their molecular gas content. In addition, update the cosmology, introduce a more accurate treatment of dynamical friction acting on satellite galaxies, and update the stellar population model. The new model is able to simultaneously explain both the observed evolution of the K-band LF and stellar MF, 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 LCDM 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 form the far-UV to sub-mm and redshifts from z=0 to 6, and is found to be generally successful. These observations include the optical and near-IR LF, HI MF, Tully-Fisher relation, fraction of early type galaxies, metallicity-luminosity relation and size-luminosity relation at z=0, as well as far-IR number counts, and far-UV LFs at z~3-6.
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