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The Question
(Submitted October 28, 1996)
I am an undergraduate in Astrophysics at the University of Calgary.
I am doing a small research project on the evidence for and against a black
hole at the center of the milky way. I found your email address on the
StarChild page dealing with this topic. I was wondering if you had
any suggestions of articles or books discussing this subject.
Thank you for your time.
The Answer
It is generally believed that a black hole does exist at the center of the
Milky Way galaxy. The latest value we have seen is that it has a mass of
about 2,000,000 that of the Sun. In fact, it is believed that this may be
common for most galaxies. Observational evidence supports these ideas more
and more. However, you must keep in mind that due to the large absorption
and source confusion when trying to look into the center of a galaxy, it is
very, very hard to see what's there! So we have to be clever about the
observations we make and the interpretations of these observations. This is
one reason that X-rays and gamma-rays are powerful probes in trying to answer
such questions; they are much more likely to "get out" of the
central region of the galaxy than other wavelengths.
Some references you may find useful (and which give many more references) are:
- Sky and Telescope, June 1996, p.28.
- "ASCA View of Our Galactic Center: Remains of Past Activities in
X-Rays?"
Publications of the Astronomical Society of Japan, v.48, p.249-255.
A more general Milky Way reference is Blitz, Binney, Lo, Bally & Ho 1993,
Nature 361, 417.
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