Void alignment and density profile applied to measuring cosmological parameters

TL;DR

This paper investigates the orientation and density profiles of cosmological voids using SDSS10 data, confirming the stretching effect and demonstrating that void density profiles can be used to measure cosmological parameters.

Contribution

It confirms the existence of the stretching effect in voids and applies the universal density profile to estimate cosmological parameters from observational data.

Findings

Confirmed the stretching effect using independent analysis.

Validated the universality of void density profiles.

Demonstrated void profiles as a tool for cosmological measurements.

Abstract

We study the orientation and density profiles of the cosmological voids with SDSS10 data. Using voids to test Alcock-Paczynski effect has been proposed and tested in both simulations and actual SDSS data. Previous observations imply that there exist an empirical stretching factor which plays an important role in the voids' orientation. Simulations indicate that this empirical stretching factor is caused by the void galaxies' peculiar velocities. Recently Hamaus et al. found that voids' density profiles are universal and their average velocities satisfy linear theory very well. In this article we first confirm that the stretching effect exists using independent analysis. We then apply the universal density profile to measure the cosmological parameters. We find that the void density profile can be a tool to measure the cosmological parameters.