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

TL;DR

This study investigates how the relationship between galaxy luminosity and halo mass of Luminous Red Galaxies evolves over redshift using weak lensing data from SDSS-DR10 and RCS2, revealing a consistent slope but increasing halo mass over time.

Contribution

It provides the first combined analysis of SDSS-DR10 and RCS2 data to measure the evolution of the luminosity-to-halo mass relation of LRGs across redshift.

Findings

Halo concentration aligns with dark matter simulations when accounting for miscentering.

Luminosity-to-halo mass relation slope is approximately 1.4 and remains constant with redshift.

Average halo mass of LRGs increases by about 80% from z=0.6 to 0.2.

Abstract

We study the evolution of the luminosity-to-halo mass relation of Luminous Red Galaxies (LRGs). We select 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), group them into bins of absolute magnitude and redshift and measure their weak lensing signals. The source redshift distribution has a median of 0.7, which allows us to study the lensing signal as a function of lens redshift. We interpret the lensing signal using a halo model, from which we obtain the halo masses as well as the normalisations of the mass-concentration relations. We find that 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 do 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 x 10^13 h70^-1 Msun. If we extend the redshift range using the CMASS galaxies and assume that they are the progenitors of the LOWZ sample, we find that the average mass of LRGs increases by 80^{+39}_{-28} % between z=0.6 and 0.2