Investigating formation stage of black holes: nucleosynthesis and mass-spin correlation

Stellar mass black holes, formed from the core collapse of very massive,
rapidly rotating stars, are expected to exhibit a transient, hot and high
density accretion disk around them during their formation. The high
density and temperature enables them to be ideal sites for the
nucleosynthesis of heavy elements.
In this talk, I shall briefly outline the various results we have obtained
while exploring nucleosynthesis in the aforesaid accretion disks and
outflows associated with them and how the nucleosynthetic products
contaminate the galaxy.
As the black hole accretes matter from the transient disk, its mass
and spin evolves. Exploiting the fact that these disks are effective
emitters of neutrinos, we propose a semi-empirical formula correlating the
mass and spin of stellar black holes during their formation stage. We
extend this correlation further to predict the spin of several
supermassive black holes.