Voids in massive neutrino cosmologies
  Cosmic voids are a promising environment to characterize neutrino-induced
effects on the large-scale distribution of matter in the universe. We perform a
comprehensive numerical study of the statistical properties of voids,
identified both in the matter and galaxy distributions, in massive and massless
neutrino cosmologies. The matter density field is obtained by running several
independent $N$-body simulations with cold dark matter and neutrino particles,
while the galaxy catalogs are modeled by populating the dark matter halos in
simulations via a halo occupation distribution (HOD) model to reproduce the
clustering properties observed by the Sloan Digital Sky Survey (SDSS) II Data
Release 7. We focus on the impact of massive neutrinos on the following void
statistical properties: number density, ellipticities, two-point statistics,
density and velocity profiles. Considering the matter density field, we find
that voids in massive neutrino cosmologies are less evolved than those in the
corresponding massless neutrinos case: there is a larger number of small voids
and a smaller number of large ones, their profiles are less evacuated, and they
present a lower wall at the edge. Moreover, the degeneracy between $\sigma_8$
and $\Omega_{\nu}$ is broken when looking at void properties. In terms of the
galaxy density field, we find that differences among cosmologies are difficult
to detect because of the small number of galaxy voids in the simulations.
Differences are instead present when looking at the matter density and velocity
profiles around these voids.
