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Recent observations discovered really massive black holes, up to $20-40$ billions Solar masses.

Now, according to an recent study and various computer simulations (I'm sorry, I don't have any reference for this, if not a paragraph on a scientific magazine), in a complete ideal case a black hole would grow about $2$ millions Solar masses in $2$ millions years.

Given that, a $20$ billions Solar masses black hole shouldn't exist because the Universe is just $13.7$ billions years. But ok, the simulation indicated an "ideal case" so one should argue about this before.

In any case, there is something I don't get: how is it possible for a $20-40$ billions Solar masses black hole to exist?

A black hole is created by the collapse of a star (according to some criteria and so on), and stars usually live for billions years. So I do expect that a $30$ billions Solar masses black hole has to be really really old, like it does exist since a "short" time after the Big Bang.

How is that possible? How does huge massive black holes have been created?

Something useful maybe

Abstract of the paper I was referring to


And the complete article (hacked)



marked as duplicate by John Rennie black-holes Apr 2 '16 at 14:08

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  • $\begingroup$ Computer simulations are always GIGO. If they don't agree with observation, we scrap them and replace them with new ones that work better. Unless you can find a citation for the original work, it's hard to say what's wrong with its assumptions. As for the formation of galaxies and galactic black holes in the early universe... I would call that a pretty big black hole of knowledge, right now, especially since we don't know enough about dark matter, yet. $\endgroup$ – CuriousOne Apr 2 '16 at 13:57
  • $\begingroup$ @CuriousOne I'm searching for the English paper! I hope to find the original paper so I'll link here! $\endgroup$ – Les Adieux Apr 2 '16 at 13:59
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    $\begingroup$ You might be interested in this paper about the formation of supermassive black holes in the Illustris simulation, a detailed cosmological model. Page 3 notes they start the early stage of the simulation by seeding it with black holes of mass around 10^5 times that of the Sun, and p. 7 notes that by z < 2 (cosmological time measured by redshift) the simulation has produced black holes with mass around 10^10 times the Sun. P. 8 also says that the way galaxies and supermassive black holes co-evolve is realistic. $\endgroup$ – Hypnosifl Apr 2 '16 at 14:36
  • $\begingroup$ Even if an idea; black hole would grow about 22 millions Solar masses in 22 millions years it doesn't mean they all started out the same size. $\endgroup$ – Bill Alsept Apr 2 '16 at 18:41