Credit: NASA/CXC/SAO
A Jet in the Distant Past
The active galaxy PKS 0637-752 is located so far from earth that it takes
light from the galaxy 6 billion years to reach us. The galaxy is
called an "active" galaxy since it generates an extraordinary amount of
energy from a very small region, the galactic nucleus, at the center of
the galaxy. This region is thought to contain a supermassive black hole
which is only about the size of our solar system but which puts out more
energy than the rest of the galaxy. The nucleus also produces a beam of
radiation, called a jet, which extends far into space. Active galaxies are
bright X-ray sources, and X-ray emission can tell us a great deal about the
physical conditions near the supermassive black hole. The image above is a
picture of the X-ray
emission from PKS 0637-752 obtained with the ACIS camera,
showing X-rays from the galaxy's nucleus on the left and the jet of X-rays
extending to the right. The jet is about 200,000 lightyears long - it
takes light 200,000 years to go from one end of the jet to the other.
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Page Author: Dr. Michael F.
Corcoran
Last modified October 16, 2000
