Programme by Session

With the detection of 40-50msun binary black holes (BH) from LIGO/VIRGO, and if we assume they come from stellar sources, then what can we learn about their progenitors? Massive stars are expected to undergo pulsational pair instabilities leading to a core collapse supernovae (PPISN) leaving behind BH’s in the mass range detected by LIGO/VIRGO. More massive stars are expected to be completely disrupted in a pair instability supernovae (PISN), leaving no remnant. The boundary between these fates sets the second black hole mass gap. In this talk I will show how the location of the second black hole mass gap can be used to constrain stellar astrophysics by understanding the progenitors of the binary black holes. This can be achieved even without detailed knowledge of the environment in which the black holes formed, as I will show how the second black hole mass gap is independent of the host environment. I will show how the maximum mass black hole LIGO/VIRGO is sensitive to uncertain nuclear reaction rates, and how we can then use the maximum mass to constrain the nuclear reaction rates.