The X-ray view is in marked contrast to the view with an optical telescope. Optically, the galaxy is a stately spiral lit by the glow of about fifty billion stars slowly evolving over millions and billions of years.
This tranquil scene is interrupted about once a century with a supernova that signals the death of a star, and in many cases the formation of a neutron star or black hole. It was the detection of such a supernova in 1999 that triggered the subsequent series of Chandra observations.
The supernova appears in the panels on days 4 and 49 as the faint source at the five o’clock position just below the diffuse glow in the center of the image. The supernova faded in a few months, but the Chandra observations continued on five more occasions in coordination with the Hubble Space Telescope and the Very Large Array radio telescope. This collaboration produced a valuable data set of long term radio, optical and X-ray observations of the galaxy.
Of particular note is an extremely bright (white) X-ray source that appears in all panels at the nine o’clock position. This source is located in a group of massive stars in one of the outer spiral arms of the galaxy. It is likely a black hole formed relatively recently (in the last million years or so) when a massive star exhausted its nuclear fuel, exploded as a supernova and left behind a black hole which is now pulling in gas from a companion star |
