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