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Sagittarius A*: NASA'S Chandra Catches Our Galaxy's Giant Black Hole Rejecting Food
Sagittarius A*
Sagittarius A*
Sagittarius A*

  • New Chandra results help explain why gas near the Milky Way's supermassive black hole is so faint in X-rays.

  • Less than 1% of the material in the black hole's gravitational grasp appears to actually reach the event horizon.

  • To obtain these results, Chandra performed one of its longest observing campaigns ever - equivalent to over 5 weeks of observing time.

The center of the Milky Way galaxy, with the supermassive black hole Sagittarius A* (Sgr A*) located in the middle, is revealed in these images. As described in our press release, astronomers have used NASA's Chandra X-ray Observatory to take a major step in understanding why gas around Sgr A* is extraordinarily faint in X-rays.

The large image contains X-rays from Chandra in blue and infrared emission from the Hubble Space Telescope in red and yellow. The inset shows a close-up view of Sgr A* only in X-rays, covering a region half a light year wide. The diffuse X-ray emission is from hot gas captured by the black hole and being pulled inwards. This hot gas originates from winds produced by a disk-shaped distribution of young massive stars observed in infrared observations (mouse over the image for the distribution of these massive stars).

These new findings are the result of one of the biggest observing campaigns ever performed by Chandra. During 2012, Chandra collected about five weeks worth of observations to capture unprecedented X-ray images and energy signatures of multi-million degree gas swirling around Sgr A*, a black hole with about 4 million times the mass of the Sun. At just 26,000 light years from Earth, Sgr A* is one of very few black holes in the Universe where we can actually witness the flow of matter nearby.

Illustration of Sagittarius A*

The authors infer that less than 1% of the material initially within the black hole's gravitational influence reaches the event horizon, or point of no return, because much of it is ejected. Consequently, the X-ray emission from material near Sgr A* is remarkably faint, like that of most of the giant black holes in galaxies in the nearby Universe.

The captured material needs to lose heat and angular momentum before being able to plunge into the black hole. The ejection of matter allows this loss to occur.

This work should impact efforts using radio telescopes to observe and understand the "shadow" cast by the event horizon of Sgr A* against the background of surrounding, glowing matter. It will also be useful for understanding the impact that orbiting stars and gas clouds might make with the matter flowing towards and away from the black hole.

The paper is available online and is published in the journal Science. The first author is Q.Daniel Wang from University of Massachusetts at Amherst, MA; the co-authors are Michael Nowak from Massachusetts Institute of Technology (MIT) in Cambridge, MA; Sera Markoff from University of Amsterdam in The Netherlands, Fred Baganoff from MIT; Sergei Nayakshin from University of Leicester in the UK; Feng Yuan from Shanghai Astronomical Observatory in China; Jorge Cuadra from Pontificia Universidad de Catolica de Chile in Chile; John Davis from MIT; Jason Dexter from University of California, Berkeley, CA; Andrew Fabian from University of Cambridge in the UK; Nicolas Grosso from Universite de Strasbourg in France; Daryl Haggard from Northwestern University in Evanston, IL; John Houck from MIT; Li Ji from Purple Mountain Observatory in Nanjing, China; Zhiyuan Li from Nanjing University in China; Joseph Neilsen from Boston University in Boston, MA; Delphine Porquet from Universite de Strasbourg in France; Frank Ripple from University of Massachusetts at Amherst, MA and Roman Shcherbakov from University of Maryland, in College Park, MD.


Fast Facts for Sagittarius A*:
Credit  X-ray: NASA/UMass/D.Wang et al., IR: NASA/STScI
Release Date  August 29, 2013
Scale  Wide-field: 1 arcmin across (about 7.5 light years); Close-up: about 4 arcsec (about 0.5 light year)
Category  Black Holes, Milky Way Galaxy
Coordinates (J2000)  RA 17h 45m 40s | Dec -29° 00´ 28.00"
Constellation  Sagittarius
Observation Date  38 pointings between 6 Feb and 29 Oct, 2012
Observation Time  833 hours 20 min (34 days 17 hours 20 min)
Obs. ID  13838-13857, 14392-94, 14413, 14414, 14427, 14432, 14438, 14439, 14460-14466, 14468, 15568, 15570
Instrument  ACIS
Also Known As Galactic Center
References Wang, Q.D. et al., 2013, Science (in press); arXiv:1307.5845
Color Code  Close-up image: X-ray (Blue), Wide-field image: X-ray (Blue); IR (Red & Yellow)
Distance Estimate  About 26,000 light years
distance arrow
Visitor Comments (4)

The way how stars and galaxies work, It s good to stretch our minds and study outer space where trillions of the stars a smallness does erase. With light-years in the billions we cannot realize the vastness of our space that all around us lies. It is the star dust that makes me wonder how the endless time itself was created. But I still have a question to ask, from planets to stars to black holes, is it true that the Andromeda Galaxy is moving toward us?

Posted by Ivan Sanchez Valencia on Wednesday, 01.10.18 @ 19:44pm

I do not understand much of this but I liked the blue and magenta blobs all spotted with intense white, thanks.

Posted by Torsten Borg on Saturday, 11.16.13 @ 09:41am

Thanks for making such wonderful stuff as this available to those of us who are fascinated by the existence of all the known and unknown "celestial bodies"? and of the myriad implications to questions relating to the origin of man, among many others. I love sharing these things with my grandchildren!

Posted by Lucy Van Wagner on Friday, 09.20.13 @ 13:39pm

Considering our system isn't active or peculiar, we do live in an awesome place! Also new research suggests that the Magellanic Clouds are not true companions of the Milky Way but might simply be passing through.

Posted by Vencel on Friday, 09.13.13 @ 21:10pm

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Press Room: Sagittarius A*
For Kids: Sagittarius A*
Blog: Too Hot to Swallow
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