The anisotropies of the Cosmological Gravitational Wave Background (CGWB)
retain information about the primordial mechanisms that source the
gravitational waves and about the geometry and the particle content of the
universe at early times. In this work, we discuss in detail the computation of
the angular power spectra of CGWB anisotropies and of their cross correlation
with Cosmic Microwave Background (CMB) anisotropies, assuming different
processes for the generation of these primordial signals. We present an
efficient implementation of our results in a modified version of CLASS which
will be publicly available. By combining our new code GW_CLASS with
MontePython, we forecast the combined sensitivity of future gravitational wave
interferometers and CMB experiments to the cosmological parameters that
characterize the cosmological gravitational wave background.Comment: 64 pages, 16 figures. V2 matches the version published by JCAP.
GW_CLASS is publicly available on the class_public git repository as a branch
GW_CLASS, https://github.com/lesgourg/class_public/tree/GW_CLASS (For details
on installation and usage, follow the instructions in the README.