X-ray & Optical Images of NGC 922
NGC 922 was formed by the collision between two galaxies - one seen in the images from Chandra and Hubble and another located outside the field of view. This collision triggered the formation of new stars in the shape of a ring. Some of these were massive stars that evolved and collapsed to form black holes. Astronomers are studying NGC 922 and other galaxies to determine the galactic composition that produces the biggest stellar-mass black holes.
(Credit: X-ray (NASA/CXC/SAO/A.Prestwich et al); Optical (NASA/STScI))