  We present the first predictions for the angular power spectrum of the
astrophysical gravitational wave background constituted of the radiation
emitted by all resolved and unresolved astrophysical sources. Its shape and
amplitude depend on both the astrophysical properties on galactic scales and on
cosmological properties. We show that the angular power spectrum behaves as
$C_{\ell}\propto 1/{\ell}$ on large scales and that relative fluctuations of
the signal are of order 30% at 100 Hz. We also present the correlations of the
astrophysical gravitational wave background with weak-lensing and galaxy
distribution. These numerical results pave the way to the study of a new
observable at the crossroad between general relativity, astrophysics and
cosmology.
