In 2013, astronomers announced they had discovered a magnetar exceptionally close to the supermassive black hole
Magnetars are dense, collapsed stars (called "neutron stars") 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 mass black hole 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.
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 supermassive black hole.
These results appear in Monthly Notices of the Royal Astronomical Society in a paper led by the PhD student Francesco Coti Zelati (Universita' dell' Insubria, University of Amsterdam, INAF-OAB), within a large international collaboration including N. Rea (University of the Amsterdam, CSIC-IEEC), A. Papitto, D. Viganò (CSIC-IEEC), J. A. Pons (Universitat d'Alacant), R. Turolla (Universita' di Padova, MSSL), P. Esposito (INAF, CfA), D. Haggard (Amherst college), F. K. Baganoff (MIT), G. Ponti (MPE), G. L. Israel, S. Campana (INAF), D. F. Torres (CSIC-IEEC, ICREA), A. Tiengo (IUSS, INAF), S. Mereghetti (INAF), R. Perna (Stony Brook University), S. Zane (MSSL), R. P. Mignani (INAF, University of Zielona Gora), A. Possenti, L. Stella (INAF).
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for the agency's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
This is one of your best articles. It's great how all of them give so much scientific detail, but are readily accessible to people like me. I have no formal education in the topic, but all my life I've been looking up. Thank you, Chandra and her handlers.
Posted by George William Branchaud, Jr. on Saturday, 03.10.18 @ 12:10pm
This object "Magnetar" will eventually merge with the black hole with a powerful burst of X-rays. However, this may happen after a pretty large period depending on its motion through a spiraling orbit towards our BH.
Posted by Manoranjan Dash on Sunday, 12.10.17 @ 08:35am
Isn't this neutron star just like nuclear material waiting to be split? Is this going to create a problem? I think so, what do you think?
Posted by Ken Sidebottom on Monday, 04.24.17 @ 22:02pm
I know normal black hole in neutron star collision can generate very powerful supernova. But I am thinking that this magnetar will not trouble much. Because black hole must suck it or even if blast is there, black hole may suck whole energy. Am I right?
Posted by ravama on Sunday, 11.1.15 @ 14:13pm
Does this Magneter near the SMBH at the center of the Milky way galaxy and two 25 Lt yrs long bubbles at each side of Milky way galaxy near the center has any relation?
Posted by Pijush Banerjee on Tuesday, 06.30.15 @ 06:56am
Will ultimately the magnetar 1745-2900 merge with the Supermassive black hole?
Posted by k.duorah on Thursday, 06.11.15 @ 16:10pm
Because SGR 1745-2900 is located so close to the galactic center it isn t detectable with optical telescopes as there is an enormous amount of gas and dust along the line of sight to us.
However, optical observations have been performed of other magnetars, eg
Posted by CXC on Friday, 05.22.15 @ 10:38am
I wanted to know whether this SGR was observed in the visible spectrum during the outburst that lead to its discovery.
Is there any technology available to observe SGRs in the visible spectrum in real time at this moment? What intensity peak could it have in the visible spectrum according to the X-Ray and other band data?
Posted by Charly on Tuesday, 05.19.15 @ 01:53am
Thank you all. Very useful.
Posted by Konrad von Austerlitz on Thursday, 05.14.15 @ 12:39pm