Title: Formation of coalescing stellar binary black holes:
What have we learnt from gravitational-wave observations so far

Abstract: The detection of gravitational waves from coalescing binary black holes by the LIGO/Virgo observatories network  allowed for the first time the direct observation of stellar-mass black holes, while the simultaneous gravitational wave and electromagnetic signal from the merger of two neutron stars provided the first direct evidence for origin of short gamma-ray bursts. These gravitational wave events, complemented by a half-a-century-long history of indirect observations of accreting compact objects in X-ray binaries, can give us now a more complete picture of the formation and evolution of binary stellar systems containing compact objects. At the same time, they also revealed weaknesses of the theories of stellar structure, binary evolution and compact object formation. In this talk, I will briefly review the current observed sample of gravitational-wave detections (the GWTC-3 catalogue) and their astrophysical implications, and discuss the different formation pathways that have been proposed in the literature to explain the properties of the observed populations. I will then highlight results from recent studies that aim at constraining the formation theories of  coalescing double compact objects by statistically comparing them with the observed sample, as well as other potential electromagnetic counterparts or  precursors. Finally, I will close with a discussion of  the “next-generation” models of double compact object formation that we are currently working on and what we expect that we will learn from them.