# The statistics of voids as a tool to constrain cosmological parameters: sigma 8 and Omega m h - Astrophysics > Cosmology and Nongalactic Astrophysics

The statistics of voids as a tool to constrain cosmological parameters: sigma 8 and Omega m h - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We present a general analytical formalism to calculate accurately severalstatistics related to underdense regions in the Universe. The statistics arecomputed for dark matter halo and galaxy distributions both in real space andredshift space at any redshift. Using this formalism, we found that voidstatistics for galaxy distributions can be obtained, to a very goodapproximation, assuming galaxies to have the same clustering properties ashalos above a certain mass. We deducted a relationship between this mass andthat of halos with the same accumulated number density as the galaxies. We alsofound that the dependence of void statistics on redshift is small. Forinstance, the number of voids larger than 13 Mpc-h defined to not containgalaxies brighter than M r=-20.4 +5logh change less than 20% between z=1 andz=0. However, the dependence of void statistics on sigma 8 and Omega m h isconsiderably larger, making them appropriate to develop tests to measure theseparameters. We have shown how to efficiently construct several of these testsand discussed in detail the treatment of several observational effects. Theformalism presented here along with the observed statistics extracted fromcurrent and future large galaxy redshift surveys will provide an independentmeasurement of the relevant cosmological parameters. Combining thesemeasurements with those found using other methods will contribute to reducetheir uncertainties.

Author: ** Juan Betancort-Rijo IAC, Santiago G. Patiri Case, Francisco Prada IAA-CSIC, Antonio Enea Romano Kyoto**

Source: https://arxiv.org/