The Quiet Sagittarius A
Credit & Copyright:
Credit:
X-ray - NASA /
CXC /
Q. Daniel Wang (UMASS) et al.,
IR - NASA/STScI
Explanation:
Hot gas is hard to swallow.
At least
that seems to be true for the supermassive black hole
at the center of our Milky Way Galaxy.
Known as source
Sagittarius A*,
the Milky Way's black hole is
centered in this infrared (red and yellow hues) and X-ray (blue)
composite.
Based on data from an
extensive campaign
of observations by the orbiting Chandra X-ray telescope, the diffuse
emission surrounding the black hole is seen in the close-up inset,
the inset field spanning about 1/2 light-year across the galactic center some
26,000 light-years away.
Astronomers have found that the X-ray emission originates in hot gas
drawn from the winds of massive young stars in the region.
The Chandra data
indicate that only about 1% or less of the gas within the
black hole's gravitational influence ever reaches the event horizon,
losing enough heat and angular momentum to fall into the black hole,
while the rest of the gas escapes in an outflow.
The result explains
why the Milky Way's black hole is so quiet,
much fainter than might be
expected in energetic X-rays.
It likely holds for most supermassive black holes
in galaxies in the nearby Universe.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
