Day 1364

Monday.

1802.00734
Unveling Galaxy Bias via the Halo Model, KiDS and GAMA
Dvornik, et al

Measure the projected galaxy clustering and GGL signals using GAMA and KiDS to study galaxy bias.  Use the concept of non-linear and stochastic galaxy biasing in the framework of halo occupation statistics to constraint the parameters of the halo occupation statistics and to unveil the origin of galaxy biasing.  The bias function Gamma_{gm}(r_p), where r_p is the projected comoving separation, is evaluated using the analytical halo model from which the scale dependence of Gamma_gm(r_p), and the origin of the non-linearity and stochasticity in halo occupation models can be inferred.  The observations unveil the physical reason for the non-linearity and stochasticity, further confirmed using hydrodynamical simulations, with the stochasticity mostly originating from the non-Poissonian behavior of satellite galaxies in the DM haloes and their spatial distribution, which does not follow the spatial distribution of DM in the halo.  The observed non-linearity is mostly due to the presence of the central galaxies, as was noted from previous theoretical work on the same topic.  Also see that overall, more massive galaxies reveal a stronger scale dependence, and out to a larger radius.  The results show that a wealth of information about galaxy bias is hidden in halo occupation models.  These models should therefore be used to determine the influence of galaxy bias in cosmological studies.