Non-fiducial cosmological test from geometrical and dynamical
  distortions around voids
  We present a new cosmological test using the distribution of galaxies around
cosmic voids without assuming a fiducial cosmology. The test is based on a
physical model for the void-galaxy cross-correlation function projected along
and perpendicular to the line of sight. We treat correlations in terms of
void-centric angular distances and redshift differences between void-galaxy
pairs, hence it is not necessary to assume a fiducial cosmology. This model
reproduces the coupled dynamical (Kaiser effect, RSD) and geometrical
(Alcock-Paczynski effect, GD) distortions that affect the correlation
measurements. It also takes into account the scale mixing due to the projection
ranges in both directions. The model is general, so it can be applied to an
arbitrary cylindrical binning scheme, not only in the case of the projected
correlations. It primarily depends on two cosmological parameters: $\Omega_m$,
the matter fraction of the Universe today (sensitive to GD), and $\beta$, the
ratio between the growth rate factor of density perturbations and the tracer
bias (sensitive to RSD). In the context of the new generation of galaxy
spectroscopic surveys, we calibrated the test using the Millennium XXL
simulation for different redshifts. The method successfully recovers the
cosmological parameters. We studied the effect of measuring with different
projection ranges, finding robust results up to wide ranges. The resulting data
covariance matrices are relatively small, which reduces the noise in the
Gaussian likelihood analysis and will allow the usage of a smaller number of
mock catalogues. The performance evaluated in this work indicates that the
developed method is a promising test to be applied on real data.
