Abstract: How did “they” form? This is one of the primary questions that any of us asked ourselves after learning that LIGO had detected a pair of remarkably heavy stellar-mass black holes, with masses significantly higher than any stellar mass black hole known so far. What do these remarkable detections tell us about the turbulent lives and endpoints of the very massive stars were their progenitors?
I will try to give an accessible overview of recent progress in the field of massive stars evolution in the context of gravitational wave detections.I will highlight new insight and progress, but also the large gaps in our knowledge.
I will briefly summarize the models that have been proposed so far to explain the formation of binary black holes, expanding on the most recently proposed model involving chemically homogeneous evolution. I will then discuss the formation channels for binary neutron stars and try to address the crucial question: What are likely to be the most fundamental lessons that gravitational wave detections teaching us about stellar astrophysics.