  We investigate the merging rates of compact binaries in galaxies, and the
related detection rate of gravitational wave (GW) events with AdvLIGO/Virgo and
with the Einstein Telescope. To this purpose, we rely on three basic
ingredients: (i) the redshift-dependent galaxy statistics provided by the
latest determination of the star formation rate functions from
UV+far-IR/(sub)millimeter/radio data; (ii) star formation and chemical
enrichment histories for individual galaxies, modeled on the basis of
observations; (iii) compact remnant mass distribution and prescriptions for
merging of compact binaries from stellar evolution simulations. We present
results for the intrinsic birthrate of compact remnants, the merging rates of
compact binaries, GW detection rates and GW counts, attempting to differentiate
the outcomes among BH-BH, NS-NS, and BH-NS mergers, and to estimate their
occurrence in disk and spheroidal host galaxies. We compare our approach with
the one based on cosmic SFR density and cosmic metallicity, exploited by many
literature studies; the merging rates from the two approaches are in agreement
within the overall astrophysical uncertainties. We also investigate the effects
of galaxy-scale strong gravitational lensing of GW in enhancing the rate of
detectable events toward high-redshift. Finally, we discuss the contribution of
undetected GW emission from compact binary mergers to the stochastic
background.
