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.
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*:
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"
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
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
