Taking advantage of photometric galaxy catalogues to determine the halo occupation distribution

FACUNDO RODRIGUEZ; MANUEL MERCHÁN; MARIOS AGUSTÍN SGRÓ

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2015 vol. 580 p. 86 - 94

0004-6361

Context. Halo occupation distribution (HOD) is a powerful statistic that allows the study of several aspects of the matter distribu-tion in the Universe, such as evaluating semi-analytic models of galaxy formation or imposing constraints on cosmological models.Consequently, it is important to have a reliable method for estimating this statistic, taking full advantage of the available informationon current and future galaxy surveys.Aims. The main goal of this project is to combine photometric and spectroscopic information using a discount method of backgroundgalaxies in order to extend the range of absolute magnitudes and to increase the upper limit of masses in which the HOD is esti-mated. We also evaluate the proposed method and apply it to estimating the HOD on the Sloan Digital Sky Survey Data Release 7(SDSS DR7) galaxy survey.Methods. We propose the background subtraction technique to mel information provided by spectroscopic galaxy groups and photo-metric survey of galaxies. To evaluate the feasibility of the method, we implement the proposed technique on a mock catalogue builtfrom a semi-analytic model of galaxy formation. Furthermore, we apply the method to the SDSS DR7 using a galaxy group cataloguetaken from spectroscopic version and the corresponding photometric galaxy survey.Results. We demonstrated the validity of the method using the mock catalogue. We applied this technique to obtain theSDSS DR7 HOD in absolute magnitudes ranging from M = −21.5 to M = −16.0 and masses up to 1015 M throughout thisrange. On the brighter extreme, we found that our results are in excellent agreement with those obtained in previous works.