Lensing results from the Red-sequence Cluster Survey

TL;DR

This paper reports weak lensing measurements from the Red-Sequence Cluster Survey, including cosmic shear, dark matter halo properties, and galaxy biasing, providing new constraints on halo extent and scale-dependent bias.

Contribution

It introduces the first constraints on dark matter halo truncation and analyzes scale-dependent galaxy biasing using RCS data.

Findings

Upper limit on halo truncation parameter s<470 h^{-1} kpc

Bias parameter b varies with scale

Galaxy-mass cross-correlation coefficient r=0.57 at 0.5 h^{-1} Mpc

Abstract

We present a variety of weak lensing results based on the ongoing analysis of R_C-band imaging data from the Red-Sequence Cluster Survey (RCS). We briefly discuss the weak lensing signal induced by intervening large scale structure (cosmic shear), and study the properties of the dark matter halos surrounding galaxies with 19.5<R_C<21 (which have a median redshift of z=0.35) using a parametrized mass model for the galaxy mass distribution. This allows us for the first time to constrain the extent of the halos. We find a robust upper limit for the truncation parameter s<470 h^{-1} kpc (99.7% confidence). We also study the biasing properties of these galaxies as a function of scale. We find that both the bias parameter b and the galaxy-mass cross-correlation coefficient r vary with scale (on scales 0.1-6 h^{-1} Mpc). Interestingly, we find that r=0.57^{+0.08}_{-0.07} on scales ~0.5 h^{-1} Mpc.