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

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(70)(-2) L-(c) and 2 x 10(11) h(70)(-2) M-circle dot 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(-0.07)(+0.06) x 10(13) h(70)(-1) M-circle dot for red galaxies, while for blue galaxies the best-fitting slope is 1.09(-0.13)(+0.20) and the normalization is 0.18(-0.05)(+0.04) x 10(13) h(70)(-1) M-circle dot. Similarly, we find a best-fitting slope of 1.36(-0.07)(+0.06) and a normalization of 1.43(-0.08)(+0.11) x 10(13) h(70)(-1) M-circle dot for the stellar mass-halo mass relation of red galaxies, while for blue galaxies the corresponding values are 0.98(-0.07)(+0.08) and 0.84(-0.16)(+0.20) x 10(13) h(70)(-1) M-circle dot 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 x 10(9) h(70)(-2) M-circle dot. 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 from galaxy-galaxy lensing that blue galaxies reside in less clustered environments than red galaxies. We also find that the halo model, while matching the lensing signal around red lenses well, is prone to overpredicting the large-scale signal for faint and less massive blue lenses. This could be a further indication that these galaxies tend to be more isolated than assumed.