Rahul Kannan, G. S. Stinson, A. V. Macciò, Chris Brook, Simone M. Weinmann, James Wadsley, H. M. P. Couchman
We present a cosmological hydrodynamical simulation of a representative volume of the Universe, as part of the Making Galaxies in a Cosmological Context (MaGICC) project. MaGICC uses a sub-grid feedback model that includes a thermal implementation of both supernova + early (pre-supernova) stellar feedback tuned to match the observed stellar mass evolution of an L* galaxy at high resolution. The large volume simulation tests the stellar feedback at lower resolution across a wide range of galaxy masses, morphologies, environments and merging histories. The simulated sample compares well with a wide range of observed relations of high redshift galaxies (z>=2). It matches the slope and scatter in the stellar mass-halo mass relation at low masses (M* > 5 x 10^10 Msun) as well as the Galaxy Stellar Mass Function (GSMF). The observed number density evolution of low mass galaxies is reproduced in our simulation, suggesting that our feedback implementation naturally detaches stellar mass growth from dark matter accretion history, which is a major improvement in galaxy formation models. The poor match of the stellar mass-halo mass relation and the GSMF at high masses (M* > 5 x 10^10 Msun) indicates that thermal feedback is not sufficient to limit star formation in these halos. The simulations match the observed star formation history of the Universe and the star forming main sequence . We see an increased specific star formation rate (sSFR) with redshift, in good agreement with observations that are corrected for nebular emission lines, although the simulations fall below the relation at z=2. Altogether our results suggest that early stellar feedback, in conjunction with supernovae feedback, plays a major role in regulating the properties of low mass galaxies at high redshift.
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http://arxiv.org/abs/1302.2618
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