How do Intermediate-Mass Black Holes Form?
At right is an artist’s conception of what an intermediate-mass accreting black hole would look like. Now, the whole reason why these objects are so exciting is that most of the objects that we know to contain black holes are thought to have either stellar mass black holes or supermassive black holes. There is a clear explanation of how these two types of black holes formed. Supernovae explosions leave behind neutron stars and black holes and the black holes formed in this way can be as large as about 20 solar masses. It is not really known how supermassive black holes formed, but one theory is that they formed in the early Universe when primordial gas clouds collapsed. When such large gas clouds collapse the black hole formation becomes inefficient for forming black holes of masses smaller than about a million solar masses. So, neither of these two scenarios explains how to form an intermediate mass black holes. Another theory of the formation of supermassive black holes is that they
