Anisotropic Halo Model

SGRÓ, M. A.; PAZ, D. J.; MERCHÁN, M. E.; RODRIGUEZ, F.

Florianopolis

Congreso; XIV Latin American Regional IAU Meeting; 2014

International Astronomical Union

We present an extended version of the classic halo model for the large-scale matter distribution which includes a triaxial model for the halo density profiles, a probabilistic distribution of the halo shape and a probabilistic law describing the alignment of the surrounding structure. In particular, we derive general expressions for the halo-matter cross-correlation function. Using a Monte Carlo integration method we obtain instances of the cross-correlation function depending on the directions given by halo shape axes. These functions are called anisotropic cross-correlations. We have found that our model is able to reproduce the numerical measurements of those functions over a wide range of scales, particularly in the 2-halo regime. The parameters of the model obtained by fitting numerical results recover the well known mass dependence of halo shapes and the alignment of dark matter halos with the surrounding structure. In this sense, most massive halos tend to have a less spherical shape and more prolate mass profile. In addition, we have found that taking the triaxial nature of dark matter halos into account improves at least %15 the predictions of the standard halo model (as noted by others authors before). Finally, we are working on the development of a similar model in order to compare theoretical predictions with anisotropic correlation functions measured on galaxy group catalogues. These results will appear in a forthcoming paper.