
Re: Wondering
It's been a lonnng time since I read up on this stuff, so I've probably forgotten most of it.
But I think the Supermassive Black Holes at the centre of Galaxies, are believed to have a different origin than "Stellar" Black Holes (those formed from Supernovas). My memory says there were two theories, one was simply they formed closer in time to the Big Bang and so were able to gobble far more in that condensed space than would be possible nowadays, and the other was something to do with early Dark Matter, which frankly I cant remember.
You are right the 100x limit is believed to be the biggest you could get from a single Supernova. I guess if you add them together you should be able to get above 100x, but I think there was something about inherent stability, which they thought would cause the newly formed Black Hole to shed mass.
Gahh now I'm going to have to go back and try and find all those old notes from Uni... Although they are probably massively out of date by now... :P