Diagnosis murder: Study shows supermassive black holes may strip galaxies of life

Apr 16, 2010

(PhysOrg.com) -- Black holes have long been beloved of science fiction writers for their destructive capabilities and peculiar ability to warp space time. Now a study led by researchers from The University of Nottingham reveals the awesome power of supermassive black holes — the ability to strip massive galaxies of the cool gases required to form new stars, leaving ageing red giants to splutter out of existence with no stars to replace them.

The study, led by Asa Bluck in the School of Physics and Astronomy, used images of unprecedented depth and resolution from the and the Chandra X-Ray Observatory to detect black holes in distant galaxies. Researchers looked for galaxies emitting high levels of radiation and x-rays — a classic signature of black holes devouring gas and dust through accretion, or attracting matter gravitationally.

As this matter swirls around the of a black hole it heats up and radiates energy — as an accretion disc. The study, which was funded by the Science and Technology Facilities Council and NASA and was a collaboration between researchers at The University of Nottingham and Imperial College London, gleaned some startling results. In supermassive black holes this radiation can reach huge proportions, emitting X-ray radiation in far greater quantities then is emitted by the rest of the objects in the galaxy combined — meaning that the black hole 'shines' far brighter than the entire galaxy it lies at the heart of. In fact, the amount of energy released is sufficient to strip the galaxy of gas at least 25 times over.

Results have also shown that the vast majority of the X-ray radiation present in the universe is produced in these accretion discs surrounding supermassive black holes, with a small proportion produced by all other objects, including galaxies and .

The accretions discs surrounding supermassive black holes produce so much energy that they heat up the cold gases lying at the heart of massive galaxies. The accretion disc shines across all wavelengths — from radio waves to gamma waves. This speeds up the random motions of the gas, making it rise in temperature and pushing it away from the galactic centre, where it becomes less dense. Gas needs to be cold and dense to collapse under gravity to form new stars, this resulting hot, low-density material must cool down before gravity will take effect — a process which would take longer than the age of the universe to achieve.

Old stars are therefore left to die out with no new stars replacing them, leaving the galaxy to grow dark and die. And by pushing gas away from the galactic centre, the accretion disc starves the of new material to devour, leading to its eventual demise.

"It's thought that black holes form inside their host galaxies and grow in proportion to them, forming an accretion disc which will eventually destroy the host. In this sense they can be described as viral in nature," said Asa Bluck, a PhD student at the University and a Fellow of the Royal Astronomical Society. "Massive galaxies are in the minority in our visible universe — about one in a thousand is thought to be massive, but it may be much less. And at least a third of these have supermassive black holes at their centre. That's why it's so interesting that this type of black hole produces most of the X-ray light in the universe. They are the minority but they dominate energy output."

Asa will present these results at the Royal Astronomical Society National Astronomy Meeting in Glasgow on Friday 16 April.

Explore further: Smallest known galaxy with a supermassive black hole found

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User comments : 7

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omatumr
1 / 5 (7) Apr 16, 2010
Neutron repulsion prevents the collapse of neutron stars into black hole.

This overlooked source of nuclear energy is greater than that available from fission or fusion.

Neutron repulsion in the cores of stars and galaxies is the primary energy source for the Sun and the cosmos

http://www.youtub...90qlChHY

With kind regards,
Oliver K. Manuel
Parsec
5 / 5 (1) Apr 17, 2010
Oliver - your kidding right? You are prepared to argue that some unmeasured and unknown repulsive force between neutrons is able to counteract the gravity of a collapsing neutron star? Do you have some evidence? Or theoretical underpinnings? You don't believe that nuclear reactions account for the sun's energy?

Ok, you really do have to be joking.
seneca
5 / 5 (3) Apr 17, 2010
Neutron repulsion in the cores of stars and galaxies is the primary energy source for the Sun and the cosmos
Neutron repulsion is in balance with gravity force in the cores of stars - so it cannot serve as a source of energy.

Conceptually: If some force makes star stable, it cannot make it unstable by radiating of energy at the same moment. These two results are mutually exclusive.

You apparently didn't understood it over last four years, for which you're spreading this fallacy on the web.
Shootist
5 / 5 (1) Apr 17, 2010
Neutron repulsion prevents the collapse of neutron stars into black hole.

This overlooked source of nuclear energy is greater than that available from fission or fusion.

Neutron repulsion in the cores of stars and galaxies is the primary energy source for the Sun and the cosmos

http://www.youtub...90qlChHY

With kind regards,
Oliver K. Manuel


Ollie you can do the math (or at least some can do the math).

Mass will reach the point where Space-Time is sufficiently curved that light cannot escape what now appears to be (from an outside frame) a singularity.

You really should take this up with Rosen and Schwarzschild since it is their solutions to GR that you seem to have so many issues with.
Nik_2213
not rated yet Apr 17, 2010
Aside from the neutron dispute, this suggests 'Where Are They' is *less probable* in a giant galaxy...
jonnyboy
1 / 5 (1) Apr 17, 2010
I am quite certain that Pelosi,Reed and Obama will make this illegal and thereby eliminate the problem.
in7x
1 / 5 (1) Apr 19, 2010
"Mass will reach the point where Space-Time is sufficiently curved that light cannot escape"

Correct, *IF* mass can reach that point.

What evidence is there that matter can reach said densities?