Consistency of the growth rate in different environments with the 6dF Galaxy Survey: measurement of the void-galaxy and galaxy-galaxy correlation functions

TL;DR

This paper tests gravitational physics by comparing the growth rate of cosmic structures around voids and galaxies using the 6dF Galaxy Survey, providing insights into environmental effects on cosmology.

Contribution

It introduces a method to compare growth rates around voids and galaxies within the same dataset, testing gravity models and cosmological assumptions.

Findings

Measured growth rates around voids and galaxies consistent within uncertainties.

Demonstrated environmental dependence can help distinguish between gravity theories.

Provided a new approach to test cosmological principles using large-scale structure data.

Abstract

We present a new test of gravitational physics by comparing the growth rate of cosmic structure measured around voids with that measured around galaxies in the same large-scale structure dataset, the low-redshift 6-degree Field Galaxy Survey. By fitting a self-consistent Redshift Space Distortion model to the 2D galaxy-galaxy and void-galaxy correlation functions, we recover growth rate values f\sigma_8 = 0.42 \pm 0.06 and 0.39 \pm 0.11, respectively. The environmental-dependence of cosmological statistics can potentially discriminate between modified-gravity scenarios which modulate the growth rate as a function of scale or environment and test the underlying assumptions of homogeneity and isotropy.