Halo Occupation Distribution Determination

FACUNDO RODRIGUEZ; MANUEL MERCHÁN; MARIO AGUSTÍN SGRÓ

Florianópolis

Encuentro; XIV Latin American Regional IAU Meeting; 2013

International Astronomical Union (IAU)

The current paradigm assumes that galaxies form within dark matter halos. However, the diversity of astrophysical mechanisms involving in galaxy formation do not allow to determine how many galaxies lie in a halo of a given mass. In this context, the Halo Occupation Distribution (HOD) gives the probability that a halo of mass M contains N galaxies and allows associate, in a statistics way, the amount of galaxies residing in a halo. In this work, we propose a method of background subtraction for calculate the HOD. This allows to combine spectroscopic information from catalogs of galaxy groups with photometric information from a catalog of galaxies. To evaluate the procedure, we used mock catalogs of galaxies and groups constructed with a imposed HOD. We compare this fiducial HOD with the obtained results by applying our method. Finally, we implement background subtraction in the Sloan Digital Sky Survey DR7.