The Evolution of the Stellar Mass Function of Galaxies from z=4.0 and the First Comprehensive Analysis of its Uncertainties: Evidence for Mass-dependent Evolution
Nov, 2008Citations per year
Abstract: (arXiv)
[Abridged] We present the evolution of the stellar mass function (SMF) of galaxies from z=4.0 to z=1.3 measured from a sample constructed from the deep NIR MUSYC, the FIRES, and the GOODS-CDFS surveys, all having very high-quality optical to mid-infrared data. This sample, unique for its combination of depth and surveyed area, allowed us to 1) minimize the uncertainty due to cosmic variance and empirically quantify its contribution to the total error budget/ 2) probe the high-mass end with unprecedented good statistics/ 3) empirically derive the redshift-dependent completeness limits in stellar mass/ 4) probe the low-mass end of the SMF down to ~0.05 times the characteristic stellar mass. We provide, for the first time, a comprehensive analysis of random and systematic uncertainties affecting the derived SMFs. We find that the mass density evolves by a factor of ~17 since z=4.0, and a factor of ~4 since z=1.3. The evolution appears to be mostly driven by a change in the normalization Phi* but we also find evidence for evolution in the shape of the SMF, with the low-mass end evolving more rapidly than the high-mass end. This result is formally significant, but we show that it is no longer robust when the systematic uncertainties due to different SED-modeling assumptions are taken into account. Taking our results at face value, we find that they are in conflict with semi-analytic models of galaxy formation.References(99)
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