Stephan’s Quintet, a compact group of galaxies discovered about 130 years ago and located about 280 million light years from Earth, provides a rare opportunity to observe a galaxy group in the process of evolving from an X-ray faint system dominated by spiral galaxies to a more developed system dominated by elliptical galaxies and bright X-ray emission. Being able to witness the dramatic effect of collisions in causing this evolution is important for increasing our understanding of the origins of the hot, X-ray bright halos of gas in groups of galaxies.
X-RAY: NASA/CXC/CFA/E. O’SULLIVAN OPTICAL: CANADA-FRANCE-HAWAII-TELESCOPE/COELUM
Black Hole Memories • Stephan’s Quintet, a compact group of galaxies… .