View Full Version : Creation of super massive black holes

2010-Jun-07, 06:33 AM
How are super massive black holes created? Are they created by the collapse of super super giant stars or some kind of other method? Were they created at the birth of the universe or are they created gradually as the universe expands like regular black holes?

2010-Jun-07, 04:01 PM
How are super massive black holes created?

With the Overseer's supermassive pencil eraser.

OK, OK, that hypothesis is unlikely to be correct. But similar to the question of early structure formation in the universe (galaxies, etc.), the answer to supermassive black hole formation hasn't really been figured out yet.

Apparently, UC, Boulder, in 2007, had a 6000-level seminar class titled "Formation of Supermassive Black Holes," but had to widen the area of investigation since...

"The topic for the seminar is nominally the formation of supermassive black holes, but since absolutely nothing is known observationally about that, the scope has been widened somewhat..."

I think we can safely say that mergers of less than supermassive black holes play a part in this formation. Beyond that, the question is a highly active area of research. This team of Begelman, Volonteri, and Rees have published the following results of their research....

We describe a mechanism by which supermassive black holes (SMBHs) can form directly in the nuclei of protogalaxies, without the need for 'seed' black holes left over from early star formation. Self-gravitating gas in dark matter haloes can lose angular momentum rapidly via runaway, global dynamical instabilities, the so-called `bars within bars' mechanism. This leads to the rapid build-up of a dense, self-gravitating core supported by gas pressure - surrounded by a radiation pressure-dominated envelope - which gradually contracts and is compressed further by subsequent infall. We show that these conditions lead to such high temperatures in the central region that the gas cools catastrophically by thermal neutrino emission, leading to the formation and rapid growth of a central black hole.

We estimate the initial mass and growth rate of the black hole for typical conditions in metal-free haloes with Tvir ~ 104K, which are the most likely to be susceptible to runaway infall. The initial black hole should have a mass of <~20 Msolar, but in principle could grow at a super-Eddington rate until it reaches ~104-106 Msolar. Rapid growth may be limited by feedback from the accretion process and/or disruption of the mass supply by star formation or halo mergers. Even if super-Eddington growth stops at ~103-104 Msolar, this process would give black holes ample time to attain quasar-size masses by a redshift of 6, and could also provide the seeds for all SMBHs seen in the present Universe. -- Source (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006MNRAS.370..289B)

2010-Jun-07, 11:43 PM
Thanks, this answered my question for the most part.