Revealing a mini-supermassive black hole

Oct 24, 2012
Revealing a mini-supermassive black hole
One of the lowest mass supermassive black holes ever observed in the middle of a galaxy has been identified. The black hole is located in the middle of the spiral galaxy NGC 4178, shown in this image from the Sloan Digital Sky Survey. The inset shows an X-ray source at the position of the black hole, in the center of an image from NASA's Chandra X-ray Observatory. An analysis of the Chandra data, along with infrared data from NASA's Spitzer Space Telescope and radio data from the NSF's Very Large Array suggests that the black hole has a mass less than about 200,000 times that of the sun, near the extreme low-mass end of the supermassive black hole range. The host galaxy is of a type not expected to harbor supermassive black holes, suggesting that this black hole, while related to its supermassive cousins, may have a different origin. Credit: X-ray: NASA/CXC/George Mason Univ/N.Secrest et al; Optical: SDSS

One of the lowest mass supermassive black holes ever observed in the middle of a galaxy has been identified, thanks to NASA's Chandra X-ray Observatory and several other observatories. The host galaxy is of a type not expected to harbor supermassive black holes, suggesting that this black hole, while related to its supermassive cousins, may have a different origin.

The black hole is located in the middle of the spiral galaxy NGC 4178, shown in this image from the Sloan Digital Sky Survey. The inset shows an X-ray source at the position of the black hole, in the center of a Chandra image. An analysis of the Chandra data, along with infrared data from NASA's and radio data from the NSF's Very Large Array suggests that the black hole is near the extreme low-mass end of the range.

These results were published in the July 1, 2012 issue of The Astrophysical Journal by Nathan Secrest, from George Mason University in Fairfax, Virginia, and collaborators.

The properties of the X-ray source, including its brightness and spectrum - the amount of X-rays at different wavelengths - and its brightness at , suggest that a black hole in the center of NGC 4178 is rapidly pulling in material from its surroundings. The same data also suggest that light generated by this infalling material is heavily absorbed by gas and dust surrounding the black hole.

A known relationship between the mass of a black hole and the amount of X-rays and radio waves it generates was used to estimate the mass of the black hole. This method gives a black hole mass estimate of less than about 200,000 times that of the sun. This agrees with mass estimates from several other methods employed by the authors, and is lower than the typical values for supermassive of millions to billions of times the mass of the sun.

NGC 4178 is a located about 55 million light years from Earth. It does not contain a bright central concentration, or bulge, of stars in its center. Besides NGC 4178, four other galaxies without bulges are currently thought to contain supermassive black holes. Of these four black holes, two have masses that may be close to that of the black hole in NGC 4178. XMM-Newton observations of an X-ray source discovered by Chandra in the center of the galaxy NGC 4561 indicate that the mass of this black hole is greater than 20,000 times the mass of the sun, but the mass could be substantially higher if the black hole is pulling in material slowly, causing it to generate less X-ray emission. A paper describing these results was published in the October 1st, 2012 issue of The Astrophysical Journal by Araya Salvo and collaborators.

The mass of the black hole in the galaxy NGC 4395 is estimated to be about 360,000 times the mass of the sun, as published by Peterson and collaborators in the October 20, 2005 issue of the .

Previously, astronomers have found that observations of a large number of galaxies are consistent with a close correlation between the mass of a supermassive black hole and the mass of the bulge of its . Theoretical models developed to explain these results invoke mergers of galaxies, and predict that galaxies without bulges are unlikely to host supermassive black holes. The results found for NGC 4178 and the four other galaxies mentioned run counter to these predictions, and may suggest that more than one mechanism is at work in forming supermassive black holes.

Three other X-ray sources were found in the Chandra image. If they are located in NGC 4178 they are likely to be binary systems containing a black hole or neutron star. The brightest of the three sources may be an intermediate-mass black hole with a mass that is about 6,000 times that of the sun.

Explore further: Despite extensive analysis, Fermi bubbles defy explanation

More information: The paper may be found at: http://arxiv.org/abs/1205.0230.

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Lurker2358
1.7 / 5 (6) Oct 24, 2012
The results found for NGC 4178 and the four other galaxies mentioned run counter to these predictions, and may suggest that more than one mechanism is at work in forming supermassive black holes.


Why are these results surprising?

I would imagine that objects of all sizes form from all the same processes, just on varying scales. Namely collisions and accretions.

So what? We've seen white dwarf mergers, supposedly, so we know old stars can suddenly collide either in head on collisions or through frame dragging or other mechanisms. Why is it such a stretch to realize that once you have a black hole, all it takes is a few more lucky collisions or captures and it's suddenly ten or twenty or hundreds of times larger?

What's the big deal? If a rogue black hole passes through a star cluster and slams into one of them, it could take down the whole cluster in one gulp, and still have enough momentum to carry the entire mass into another cluster over time...viola exponential growth.
Tuxford
1.4 / 5 (10) Oct 24, 2012
More good news! LaViolotte's growth model holds here too. The core is growing the galaxy, rather than the reverse. (See them squirm to explain how this can be.) A bulge will form, as the core grey hole star grows in size. Eventually, the galaxy becomes a giant elliptical.

http://phys.org/n...ync.html
Jonseer
1.3 / 5 (3) Oct 24, 2012
I guess astronomers have to prove things, which is fine.

the problem is until they are proven, all too often the lack of proof is spoken of as proof of not existing.

ALL galaxies have black holes at their center.

The fact we cannot detect them yet should NOT be proof they don't exist.

Even compact globular clusters the remains of dwarf galaxies in our our galaxy will eventually be revealed to have black holes in the center.

Of course NO evidence of this has been found, so naturally the false conclusion is they don't have one.

The proper conclusion is we haven't found any evidence yet.

Finding such evidence even in plain sight is not a given.

FIRST someone must be motivated to look AND obtain funding and sponsorship to make that search.

ONLY then can we expect results.

The efforts so far have been disjointed and individualistic meaning drawing any conclusions from it is stupid.

And this article demonstrates this truth pretty well.
Lurker2358
1 / 5 (4) Oct 25, 2012
Jonseer:

One of the things about astronomy that always perplexes me is they spend a lot of time studying things that don't seem to relevant to answering fundamental questions about anything, and then we get scads of articles detailing "no brainer" findings that should have been pretty obvious from the beginning.

I don't know why scientists have such superstitious beliefs that certain ranges of masses of black holes shouldn't exist or pretend not to have a way to explain them. Obviously they exist, and obviously SMBH would have been some intermediate mass (in anything looking like the standard model, since they reject anything not looking like the standard model of cosmology,) sooo...what's the deal?

They believe in little black hole and big black holes, and both are made by the collapse of matter into said super dense state, so why is it so hard to conceive that middle mass black holes obviously form through collisions of a black hole and other matter?