Black Hole-Powered Spiral Galaxy NGC 7742

Galaxy NGC 7742 in the constellation Pegasus is by no means a run-of-the-mill spiral galaxy. Instead, the galaxy contains a bright, yellow core surrounded by concentric rings of immense, blue star clusters. When examined with a spectroscope, the core of NGC 7742 is shown to contain strong emission lines, the indication of high-energy physical processes at work there. In fact, with its particular type of active galactic nucleus, NGC 7742 is classified as a Seyfert 2 active galaxy, one that is probably powered by a black hole residing in its core. The galaxy’s brightest stellar ring is about 3,000 light-years from the core. Tightly wound spiral arms are also faintly visible. Surrounding the inner ring is a wispy band of material, which is probably the remains of a once very active stellar breeding ground.