The Alcock-Paczyński test with cosmic voids
Alice PISANI, P. M. SUTTER, B. D. WANDELT, and D. H. WEINBERG
MNRAS 2014
Cosmic voids have, generally, very different shapes.
But, in a homogeneous and isotropic universe the
average real-space shape of voids is spherical .
Thus we can use stacked voids as standard spheres : objects of know ratio of radial over angular size (see left figure).
Since such ratio depends on cosmology,
the measure of the stacked void stretch is a powerful test of cosmological models:
it's the Alcock-Paczyński test. In this paper we use SDSS DR10 data to constrain the
matter density of the Universe.