Anisotropies and non-Gaussianity of the Cosmological Gravitational Wave
  Background
  The Stochastic Gravitational Wave Background (SGWB) is expected to be a key
observable for Gravitational Wave (GW) interferometry. Its detection will open
a new window on early universe cosmology and on the astrophysics of compact
objects. Using a Boltzmann approach, we study the angular anisotropies of the
GW energy density, which is an important tool to disentangle the different
cosmological and astrophysical contributions to the SGWB. Anisotropies in the
cosmological background are imprinted both at its production, and by GW
propagation through the large-scale scalar and tensor perturbations of the
universe. The first contribution is not present in the Cosmic Microwave
Background (CMB) radiation (as the universe is not transparent to photons
before recombination), causing an order one dependence of the anisotropies on
frequency. Moreover, we provide a new method to characterize the cosmological
SGWB through its possible deviation from a Gaussian statistics. In particular,
the SGWB will become a new probe of the primordial non-Gaussianity of the
large-scale cosmological perturbations.
