Çç××öúúøøóòòð Úúúúò Óö ×øøðððö Ññ×× Òòöý Ðð Óðð× Òò Øøøøö Óóðð× Blockin Blockinò Ööøø

We review the formation scenarios for binary black holes, and show that their co-alescence rate depends very strongly on the outcome of the second mass transfer. However, the observations of IC10 X-1, an binary with a massive black hole accreting from a Wolf-Rayet star proves that this mass transfer can be stable. We analyze the future evolution of IC10 X-1 and show that it is very likely to form a binary black hole system merging in a few Gyrs. We estimate the coalescence rate density of such systems to be 0.06 Mpc −3 Myr −1 , and the detection rate for the current LIGO/VIRGO of 0.69 yr −1 , a much higher value than the expected double neutron star rate. Thus the first detection of a gravitational wave source is likely to be a coalescence of a binary black hole.