I have a (probably elementary) question about the end of a massive star. I know that the two issues are a neutron star and a black hole, depending on the remaining mass of the core. In as much as I understand things, a type II supernova results from the sudden halting of the collapse of the core after the Chandrasekar limit has been passed and most protons recombined with electrons to make neutrons. Neutron degeneracy brings this collapse to a sudden end, and this sends out a powerful shockwave (together with a neutrino pulse) through the outer layers, giving rise to the massive energy release and blasting of material in the supernova. However, when the limit of neutron degeneracy is reached (I think around 2.5 solar masses for the core), this doesn't stop the collapse and we are supposed to end up with a black hole. Now, my question is: do we still have a supernova when there's a black hole formation ? Because there's not going to be a shockwave now, no ? There are probably still the neutrino's because I guess they get out before the black hole forms (not sure). That's maybe sufficient. But I thought that the main cause of a supernova was the sudden halting of the inward collapse of the outer layers, giving rise to a shock wave - halting which is, if I understand correctly, absent in the case of a BH. So is there nevertheless a supernova ? Or does the star silently go "poof" into a black hole ?