Chandra reveals wind and reflections from a black hole (Forwarded)

Steve Roy
Media Relations Dept.
Marshall Space Flight Center, Huntsville, AL

(256) 544-0034

For release: 07-11-03

Photo release no.: 03-115

Chandra reveals wind and reflections from a black hole
[http://www1.msfc.nasa.gov/NEWSROOM/n...os03-115.html]

This composite X-ray, shown in blue and green, and optical, shown in red, image
of the active galaxy, NGC 1068, shows gas blowing away in a high-speed wind from
the vicinity of a central supermassive black hole. Regions of intense star
formation in the inner spiral arms of the galaxy are highlighted by both optical
and X-ray emission.

The elongated shape of the gas cloud is thought to be due to the funneling
effect of a torus, or doughnut-shaped cloud, of cool gas and dust that surrounds
the black hole. The torus, which appears as the elongated white spot in the
accompanying three-color X-ray images, has a mass of about 5 million Suns. Radio
observations indicate that the torus extends from within a few light years of
the black hole out to about 300 light years.

The X-rays observed from the torus are scattered and reflected X-rays that are
probably coming from a hidden disk of hot gas formed as matter swirls very near
the black hole. The torus is one source of the gas in the high-speed wind, but
the hidden disk may also be involved. X-ray heating of gas further out in the
galaxy contributes to the slower, outer parts of the wind.

Observations with the spectrometers aboard NASA's Chandra X-ray Observatory
enable scientists to estimate the composition, temperature and flow velocity of
the gas. They show that the composition of the material in the wind is roughly
similar to that of the Sun's atmosphere, except for a deficit of oxygen atoms,
and that it has a temperature of about 100,000 degrees Celsius (180,000 degrees
Fahrenheit). The average gas speed is about 1 million miles per hour.

These Chandra data on NGC 1068 are consistent with a picture where the observer
is looking along the edge of a torus of cool gas and dust around a supermassive
black hole. In this case we see the indirect effects of the black hole, but do
not get a direct view. In contrast, an observer looking down into the hole of
the torus would see a brilliant black hole source (see NGC 5548, NGC 4151).

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra
program.

Credit:
X-ray: NASA/CXC/MIT/UCSB/P.Ogle et al.
Optical: NASA/STScI/A.Capetti et al.

Reference:
P. Ogle et al. 2003 Astronomy and Astrophysics, 402, 849

The image and additional information are available at:

http://chandra.harvard.edu/
and
http://chandra.nasa.gov/