A COMPREHENSIVE ANALYSIS OF UNCERTAINTIES AFFECTING THE STELLAR MASS-HALO MASS RELATION FOR 0 <z< 4

Abstract

We conduct a comprehensive analysis of the relationship between central galaxies and their host dark matter halos, as characterized by the stellar mass -halo mass (SM-HM) relation, with rigorous consideration of uncertainties. Our analysis focuses on results from the abundance matching technique, which assumes that every dark matter halo or subhalo above a specific mass threshold hosts one galaxy. We provide a robust estimate of the SM-HM relation for 0 < z < 1 and discuss the quantitative effects of uncertainties in observed galaxy stellar mass functions (GSMFs) (including stellar mass estimates and counting uncertainties), halo mass functions (including cosmology and uncertainties from substructure), and the abundance matching technique used to link galaxies to halos (including scatter in this connection). Our analysis results in a robust estimate of the SM-HM relation and its evolution from z=0 to z=4. The shape and evolution are well constrained for z < 1. The largest uncertainties at these redshifts are due to stellar mass estimates (0.25 dex uncertainty in normalization); however, failure to account for scatter in stellar masses at fixed halo mass can lead to errors of similar magnitude in the SM-HM relation for central galaxies in massive halos. We also investigate the SM-HM relation to z = 4, although the shape of the relation at higher redshifts remains fairly unconstrained when uncertainties are taken into account. We find that the integrated star formation at a given halo mass peaks at 10-20% of available baryons for all redshifts from 0 to 4. This peak occurs at a halo mass of 7 × 10 11 M ⊙ at z = 0 and this mass increases by a factor of 5 to z = 4. At lower and higher masses, star formation is substantially less efficient, with stellar mass scaling as M * ∼ M 2.3 h at low masses and M * ∼ M 0.29 h at high masses. The typical stellar mass for halos with mass less than 10 12 M ⊙ has increased by 0.3 − 0.45 dex for halos since z ∼ 1. These results will provide a powerful tool to inform galaxy evolution models.

The dark matter haloes of moderate luminosity X-ray AGN as determined from weak gravitational lensing and host stellar masses

“…To test for contamination effects, we compare our mass estimates with those from Bongiorno et al (2012) which were derived using both galaxy and AGN templates. We find an overall offset of 0.18 dex between our mass estimates which is within the expected range of systematic uncertainties (Behroozi et al 2010). More importantly, however, this mass offset does not exhibit any trends with L X suggesting that our mass estimates are robust at these moderate luminosities.…”

“…From a global perspective that includes all galaxies, tremendous progress has had been made in recent years in terms of understanding and modelling the connection between galaxy stellar mass and dark matter halo mass out to z = 1 and beyond (Mandelbaum et al 2006;More et al 2009;Behroozi, Conroy & Wechsler 2010;Moster et al 2010;Leauthaud et al 2011Leauthaud et al , 2012a. At the core of these models is the stellar-to-halo mass relation (SHMR) for central galaxies.…”

Dusty star-forming galaxies at high redshift

“…The basic construct behind these models was to utilize theoretical halo mass functions, and assign galaxies to them utilizing an abundance matching technique (e.g. Conroy & Wechsler, 2009;Behroozi et al, 2010). These would then be combined with the results of high-resolution merger calculations in order to determine the typical burst luminosity from a galaxy merger, or steady-state SFR from an isolated disk galaxy of a given mass.…”

Implications of a variable IMF for the interpretation of observations of galaxy populations

“…We can compare this rate to the rate of gas accretion onto the halo. For this we use the stellar mass-halo mass relation from Behroozi, Conroy & Wechsler (2010) to determine the halo mass (where we always use the Chabrier IMF) and the corresponding halo gas accretion rate from Correa et al (2015). At a stellar mass of 10 10 M , the accretion onto the halo is about a factor 2.5 larger than the median SFR, both for a universal Chabrier IMF and for the Vazdekis IMF.…”

“…The second column gives the corresponding median stellar mass for a metallicity-dependent Vazdekis IMF, from Figure 8. The third column gives the corresponding halo mass from Behroozi, Conroy & Wechsler (2010). The fourth column gives the median total HI plus H 2 gas mass from Bahe et al (2015) and references therein.…”