The LIGO/Virgo detections of gravitational waves from merging black holes of \simeq 30 solar mass suggest progenitor stars of low metallicity ( Z / Z _ { \odot } \lesssim 0.3 ) .
In this talk I will provide constrains on where the progenitors of GW150914 and GW170104 may have formed , based on advanced models of galaxy formation and evolution combined with binary population synthesis models .
First I will combine estimates of galaxy properties ( star-forming gas metallicity , star formation rate and merger rate ) across cosmic time to predict the low redshift BBH merger rate as a function of present day host galaxy mass , formation redshift of the progenitor system and different progenitor metallicities .
I will show that the signal is dominated by binaries formed at the peak of star formation in massive galaxies with and binaries formed recently in dwarf galaxies .
Then , I will present what very high resolution hydrodynamic simulations of different galaxy types can learn us about their black hole populations .