Super-massive Black holes: What's the mystery?

[jryan]

I have been wondering what the big mystery is regarding super massive black holes at the centers of galaxies. I was watching a documentary last night where cosmologists kept referring to the finding as a "mystery". What confuses me is that I always saw this as a given... though, for very uncomplicated reasons.

 

Since galaxies have a center of mass I would assume that the galaxies develop somewhat similar to a solar system, with the bulk of the central mass being close enough together that over time it all was pulled together. The sheer mass of the matter was creating a black hole.

 

(speaking of which: would a super massive black hole develop without burning it's nuclear fuel light a standard black hole? I assume it could as the mass could create a gravitational pull stronger than the counter pressure from nuclear fusion)

 

The remaining mass on the cusp of that critical distance then ends in an orbit around the black hole itself (in the same way that the planets are formed in a solar system).... in this case the orbiting mass is the rest of the galaxy.

[Airbrush]

Yeah, what's the mystery? Anyhow anything that is Millions or Billions of solar masses that is nearly invisible, is inherently mysterious. I sure would like to see a real picture of a supermassive black hole (SBH), other than a tiny dot.

 

So, if most galaxies are assumed to have a SBH at its' center, would that imply that most, if not all, galaxies start out as quasars, crushing dust and gas, and everything else, down to atom sized and blasting out incredible amounts of energy, continuously for millions of years, from its' poles?

 

Can the age of quasars be determined? Would all quasars, and probably all SBHs, have formed before stars formed in their galaxies? That is with the exception of mergers of SBHs when galaxies collide. Could the first "light" in the universe, after the dark ages, have been quasars forming?

Edited April 8, 2010 by Airbrush

[toastywombel]

I will comment on this one after work.

[Airbrush]

After the Big Bang cooled somewhat, and space became transparent, the expanding gas of hydrogen, helium, and only a few other light gases, there was a fairly uniform gas medium as explained by cosmic inflation. This gas clumped into regions that later became galaxies. As the gas attracted itself on massive scales, there grew huge proto-stars. Near the center of the galaxy there was much higher density of gas crashing into itself very violently, rapidly forming giant stars that immediately crashing into each other, quickly forming a great black hole before there could be any supernova. Then all hell broke loose, and the infant black hole started feeding on giant nearby stars in a frenzie, igniting the quasar.

[D H]

Since galaxies have a center of mass I would assume that the galaxies develop somewhat similar to a solar system, with the bulk of the central mass being close enough together that over time it all was pulled together. The sheer mass of the matter was creating a black hole.

That is not a good assumption. It now appears that the massive black holes formed before galaxies did, and they formed before stars. Just a couple of many articles on this topic:

 

http://www.scientificamerican.com/blog/60-second-science/post.cfm?id=which-came-firstgalaxies-or-black-h-2009-01-07

http://news.sciencemag.org/sciencenow/2009/01/07-01.html

[jryan]

That is not a good assumption. It now appears that the massive black holes formed before galaxies did, and they formed before stars. Just a couple of many articles on this topic:

 

http://www.scientificamerican.com/blog/60-second-science/post.cfm?id=which-came-firstgalaxies-or-black-h-2009-01-07

http://news.sciencemag.org/sciencenow/2009/01/07-01.html

 

The first article has an update that reopens the question of which came first. For example, that the 0.1% rule is not hard and fast for even old galaxies. And I would say that 4 galaxies is a rather small sample size for a statistical analysis of that type.

 

Such a small sample size would be adversely effected by unrelated sample errors like these massive galaxies being bright enough that we can see them while the vast majority of these early galaxies are too dark for us to see... or more hard for us to find.

 

I don't find that article a deal breaker or my assumption to be "not good" because of it. I find their conclusion to be both early and incredibly odd. I don't think their study is sufficiently robust for such a bizarre conclusion beyond "boy wouldn't that be weird?".

[Airbrush]

The center of a galaxy was an extremly dense place at a critical time during galactic formation, like our solar system forming, but on a much grander scale. The center became incredibly massive rapidly and like a cosmic vacuum cleaner sucked up all the gas in the immediate area. This rapidly formed a massive ball of hydrogen gas, over hundreds of thousands of solar masses. The SBH formed not over a period of millions of years, or even thousands or hundreds of years, but at some critical point in time it formed over a matter of minutes or a tiny fraction of a second. Even before nuclear fusion could start, it was already too massive to become a star and instantly crunched itself into a SBH. After the initial "Big Galactic Crunch" the remaining gas around the center had enough angular momentum to continue slowly feeding the new-born SBH with a steady stream of gas igniting a quasar. Over millions of years it eventually swept the center of all loose hydrogen and went dormant. Millions of years later the surrounding disk of gas gradually formed stars.

 

So maybe the formation of the central SBH happened so quickly that it created the first light in the universe after the Big Bang in a huge instantaneous flash, greater than any supernova or quasar, and a quasar was born. The stars took much longer to begin nuclear fusion.

 

From wikipedia:

 

"...Another model of supermassive black hole formation involves a large gas cloud collapsing into a relativistic star of perhaps a hundred thousand solar masses or larger. The star would then become unstable to radial perturbations due to electron-positron pair production in its core, and may collapse directly into a black hole without a supernova explosion, which would eject most of its mass and prevent it from leaving a supermassive black hole as a remnant. Yet another model involves a dense stellar cluster undergoing core-collapse as the negative heat capacity of the system drives the velocity dispersion in the core to relativistic speeds. Finally, primordial black holes may have been produced directly from external pressure in the first instants after the Big Bang."

 

http://en.wikipedia.org/wiki/Supermassive_black_hole

 

Recent news about SBH:

 

"On 4 January 2010, at the meeting of the American Astronomical Society, Julie Comerford of the University of California, Berkeley, presented evidence derived from the W.M. Keck Observatory in Hawaii and the Hubble Space Telescope of 33 merged galaxies with pairs of supermassive black holes orbiting around a common center at speeds exceeding 4,600,000 kilometres per hour (795 miles per second!)."

Edited April 10, 2010 by Airbrush