Anisotropic Halo Model

MARIO AGUSTÍN SGRÓ; DANTE PAZ; MANUEL MERCHÁN; FACUNDO RODRIGUEZ

Florianópolis

Encuentro; XIV Latin American Regional IAU Meeting; 2013

We present an extended version of the classic halomodel for the large-scale matter distribution whichincludes a triaxial model for the halo density profiles,a probabilistic distribution of the halo shape anda probabilistic law describing the alignment of thesurrounding structure. In particular, we derive generalexpressions for the halo-matter cross-correlationfunction. Using a Monte Carlo integration methodwe obtain instances of the cross-correlation functiondepending on the directions given by halo shapeaxes. These functions are called anisotropic crosscorrelations.We have found that our model is ableto reproduce the numerical measurements of thosefunctions over a wide range of scales, particularly inthe 2-halo regime. The parameters of the model obtainedby fitting numerical results recover the wellknown mass dependence of halo shapes and thealignment of dark matter halos with the surroundingstructure. In this sense, most massive halos tend tohave a less spherical shape and more prolate massprofile. In addition, we have found that taking thetriaxial nature of dark matter halos into account improvesat least %15 the predictions of the standardhalo model (as noted by others authors before).Finally, we are working on the development of a similarmodel in order to compare theoretical predictionswith anisotropic correlation functions measured ongalaxy group catalogues. These results will appearin a forthcoming paper.