This composite image of Arp 147, a pair of
interacting galaxies located about 430 million light years from Earth,
shows X-rays from the NASA’s Chandra X-ray Observatory (pink) and
optical data from the Hubble Space Telescope (red, green, blue) produced
by the Space Telescope Science Institute (STScI) in Baltimore, Maryland.
Arp 147 contains the remnant of a spiral galaxy (right) that collided
with the elliptical galaxy on the left. This collision has produced an
expanding wave of star formation that shows up as a blue ring containing
in abundance of massive young stars. These stars race through their
evolution in a few million years or less and explode as supernovas,
leaving behind neutron stars and black holes. A fraction of the
neutron stars and black holes will have companion stars, and may become
bright X-ray sources as they pull in matter from their companions. The
nine X-ray sources scattered around the ring in Arp 147 are so bright
that they must be black holes, with masses that are likely ten to twenty
times that of the Sun. |
