Evolution of the luminosity-to-halo mass relation of LRGs from a combined analysis of SDSS-DR10+RCS2

Abstract

We study the evolution of the luminosity-to-halo mass relation of luminous red galaxies (LRGs). We selected a sample of 52≠000 LOWZ and CMASS LRGs from the Baryon Oscillation Spectroscopic Survey (BOSS) SDSS-DR10 in the ~450 deg 2 that overlaps with imaging data from the second Red-sequence Cluster Survey (RCS2), grouped them into bins of absolute magnitude and redshift and measured their weak-lensing signals. The source redshift distribution has a median of 0.7, which allowed us to study the lensing signal as a function of lens redshift. We interpreted the lensing signal using a halo model, from which we obtained the halo masses as well as the normalisations of the mass-concentration relations. The concentration of haloes that host LRGs is consistent with dark-matter-only simulations once we allow for miscentering or satellites in the modelling. The slope of the luminosity-to-halo mass relation has a typical value of 1.4 and does not change with redshift, but we find evidence for a change in amplitude: the average halo mass of LOWZ galaxies increases by 25 -14 +16 % between z = 0.36 and 0.22 to an average value of (6.43 ± 0.52) × 10 13 h 70 -1 M O.. If we extend the redshift range using the CMASS galaxies and assume that they are the progenitors of the LOWZ sample, the average mass of LRGs increases by 80 +39 -28 % between z = 0.6 and 0.2.