CFHTLenS: the relation between galaxy dark matter haloes and baryons from weak gravitational lensing

Abstract

We present a study of the relation between dark matter halo mass and the baryonic content of their host galaxies, quantified through galaxy luminosity and stellar mass. Our investigation uses 154 deg 2 of Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) lensing and photometric data, obtained from the CFHT Legacy Survey. To interpret the weak lensing signal around our galaxies, we employ a galaxy-galaxy lensing halo model which allows us to constrain the halo mass and the satellite fraction. Our analysis is limited to lenses at redshifts between 0.2 and 0.4, split into a red and a blue sample. We express the relationship between dark matter halo mass and baryonic observable as a power law with pivot points of 10 11 h -2 70 L and 2 10 11 h -2 70 M for luminosity and stellar mass, respectively. For the luminosity-halo mass relation, we find a slope of 1.32 0.06 and a normalization of 1.19 +0.06 -0.07 10 13 h -1 70 M for red galaxies, while for blue galaxies the best-fitting slope is 1.09 +0.20 -0.13 and the normalization is 0.18 +0.04 -0.05 10 13 h -1 70 M . Similarly, we find a best-fitting slope of 1.36 +0.06 -0.07 and a normalization of 1.43 +0.11 -0.08 10 13 h -1 70 M for the stellar mass-halo mass relation of red galaxies, while for blue galaxies the corresponding values are 0.98 +0.08 -0.07 and 0.84 +0.20 -0.16 10 13 h -1 70 M . All numbers convey the 68 per cent confidence limit. For red lenses, the fraction which are satellites inside a larger halo tends to decrease with luminosity and stellar mass, with the sample being nearly all satellites for a stellar mass of 2 10 9 h -2 70 M . The satellite fractions are generally close to zero for blue lenses, irrespective of luminosity or stellar mass. This, together with the shallower relation between halo mass and baryonic tracer, is a direct confirmation