A gravitational wave stochastic background of astrophysical origin may have
resulted from the superposition of a large number of unresolved sources since
the beginning of stellar activity. Its detection would put very strong
constrains on the physical properties of compact objects, the initial mass
function or the star formation history. On the other hand, it could be a
'noise' that would mask the stochastic background of cosmological origin. We
review the main astrophysical processes able to produce a stochastic background
and discuss how it may differ from the primordial contribution by its
statistical properties. Current detection methods are also presented.Comment: appeared in Research in Astronomy & Astrophysics (RAA), vol 11 (2011)
as Invited paper ; 20 pages and 7 figures; version corrected after we found
an error in equation (5