Magnetar near supermassive black hole delivers surprises

Magnetar near supermassive black hole delivers surprises
Credit: NASA/CXC/INAF/F.Coti Zelati et al

In 2013, astronomers announced they had discovered a magnetar exceptionally close to the supermassive black hole at the center of the Milky Way using a suite of space-borne telescopes including NASA's Chandra X-ray Observatory.

Magnetars are dense, collapsed stars (called "") that possess enormously powerful magnetic fields. At a distance that could be as small as 0.3 light years (or about 2 trillion miles) from the 4-million-solar in the center of our Milky Way galaxy, the magnetar is by far the closest neutron star to a supermassive black hole ever discovered and is likely in its gravitational grip.

Since its discovery two years ago when it gave off a burst of X-rays, astronomers have been actively monitoring the magnetar, dubbed SGR 1745-2900, with Chandra and the European Space Agency's XMM-Newton. The main image of the graphic shows the region around the Milky Way's black hole in X-rays from Chandra (red, green, and blue are the low, medium, and high-energy X-rays respectively). The inset contains Chandra's close-up look at the area right around the black hole, showing a combined image obtained between 2005 and 2008 (left) when the magnetar was not detected, during a quiescent period, and an observation in 2013 (right) when it was caught as a bright point source during the X-ray outburst that led to its discovery.

A new study uses long-term monitoring observations to reveal that the amount of X-rays from SGR 1745-2900 is dropping more slowly than other previously observed magnetars, and its surface is hotter than expected.

Magnetar near supermassive black hole delivers surprises
This illustration shows how an extremely rapidly rotating neutron star, which has formed from the collapse of a very massive star, can produce incredibly powerful magnetic fields. Credit: NASA/CXC/M.Weiss

The team first considered whether "starquakes" are able to explain this unusual behavior. When neutron stars, including magnetars, form, they can develop a tough crust on the outside of the condensed star. Occasionally, this outer crust will crack, similar to how the Earth's surface can fracture during an earthquake. Although starquakes can explain the change in brightness and cooling seen in many magnetars, the authors found that this mechanism by itself was unable to explain the slow drop in X-ray brightness and the hot crustal temperature. Fading in X-ray brightness and surface cooling occur too quickly in the starquake model.

The researchers suggest that bombardment of the surface of the magnetar by charged particles trapped in twisted bundles of magnetic fields above the surface may provide the additional heating of the magnetar's surface, and account for the slow decline in X-rays. These twisted bundles of magnetic fields can be generated when the neutron star forms.

The researchers do not think that the magnetar's unusual behavior is caused by its proximity to a supermassive black hole, as the distance is still too great for strong interactions via magnetic fields or gravity.

Astronomers will continue to study SGR 1745-2900 to glean more clues about what is happening with this magnetar as it orbits our galaxy's .

These results appear in Monthly Notices of the Royal Astronomical Society.


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Chandra detects record-breaking outburst from Milky Way's black hole

More information: Coti Zelati, F. et al, 2015, MNRAS 449, 2685; arXiv:1503.01307. arxiv.org/abs/1503.01307
Citation: Magnetar near supermassive black hole delivers surprises (2015, May 14) retrieved 25 August 2019 from https://phys.org/news/2015-05-magnetar-supermassive-black-hole.html
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May 14, 2015
As this Magnetar spirals in some of the magnetic fields extending out from it should begin to break the speed of light. Will that put a brake on the whole thing and make it lose momentum or do those fields continue to surround it in their normal configuration and ignore their relative speed?

May 14, 2015
Magnetar status: theoretical object;
Black hole status: theroretical object:
Black matter status: ocult symbol;
Black energy status: ocult symbol:
Modern astrophysics: status politicaly correct mithology;

May 14, 2015
Something with 4 million times the mass of the sun, plus the combined gravitational effects of that dense region of the galaxy doesn't cause meaningful tidal effects on the neutron star?
I must just not be able to fathom how dense a neutron star really is, but still seems weird to me.

Shut the hell up Viko, you are the absolute worst commentator I've seen


May 15, 2015
@Viko_mx, the situation It's not as you are trying to represent it. Actually It's more like - we have more and more proofs about some new areas of science, but till we don't approve them by the scientific method, we won't call them facts. In opposite, the religion dogma is - it's a fact because it's written in one of the some thousands interpretations of something which somebody might have said some thousands years ago. So, the religious beliefs are not even considering as a "theoretical object".

May 15, 2015
Magnetar status: theoretical object;
Black hole status: theroretical object:
Black matter status: ocult symbol;
Black energy status: ocult symbol:
Modern astrophysics: status politicaly correct mithology;

All hail Satan!

YES!!! HAIL SATAN!!!

May 15, 2015
Jeffhans1: The magnetic fields can exceed light speed, just as a rotating searchlight beam can, if one measures the rotational speed at a great enough distance. There's no relativity violation because the movement doesn't involve mass, or convey information.

If there are particles trapped in the fields, they will also be accelerated, and as they approach the speed of light, they will emit radiation. The energy for this radiation comes from the magnetic field, and thus from the central object, and does slow the rotation.

References please, regarding exceeding light speed. I believe your analogy is that of an optical illusion, not reality.

May 18, 2015
I don't get how people say "Magnetar status: theoretical object;" when scientists have been studying this one in particular for almost two years now. There's even a picture of the magnetar at the top of this web page!!

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