Measuring subhalo mass in redMaPPer clusters with CFHT Stripe 82 Survey

Abstract

We use the shear catalogue from the CFHT Stripe-82 Survey to measure the subhalo masses of satellite galaxies in redMaPPer clusters. Assuming a Chabrier initial mass function and a truncated NFW model for the subhalo mass distribution, we find that the subhalo mass to galaxy stellar mass ratio increases as a function of projected halo-centric radius r(p), from M-sub/M-star = 4.43(-2.23)(+6.63) at r(p) is an element of [0.1, 0.3] h(-1) Mpc toM(sub)/M-star = 75.40(-19.09)(+19.73) at r(p) is an element of [0.6, 0.9] h(-1) Mpc. We also investigate the dependence of subhalo masses on stellar mass by splitting satellite galaxies into two stellar mass bins: 10 < log (M-star/h(-1) M-circle dot) < 10.5 and 11 < log (M-star/h(-1) M-circle dot) < 12. The best-fitting subhalomass of the more massive satellite galaxy bin is larger than that of the lessmassive satellites: log(M-sub/h(-1) M-circle dot) = 11.14(-0.73)(+0.66) (M-sub/M-star = 19.5(-17.9)(+19.8)) versus log(M-sub/h(-1) M-circle dot) = 12.38(-0.16)(+0.16) (M-sub/M-star = 21.1(-7.7)(+7.4)).