This perfectly lovely spiral galaxy might look like an ordinary spiral galaxy, and it is (for the most part). It has a central core, numerous winding spiral arms, bright regions scattered within the spiral arms that are indicative of star formation activity, and even patchy strands of dust, which are intertwined with gas.
The only thing that truly sets the galaxy, called NGC 1637, apart is the extraordinarily bright supernova that ignited in the late 1990's. When it first popped up on our radar—after being spotted by Lick Observatory's Katzman Automatic Imaging Telescope in 1999, which was built for the purpose of finding and cataloguing new supernovae—a huge outburst was made note of, which led to an increase in interest.
Today, the supernova—cataloged as SN 1999em—is one of the most well studied in memory.For instance, we know that the progenitor star was approximately 8 times heavier than our own Sun currently is, that is, until it exploded as a type IIp supernova. Furthermore, astronomers have spent a great amount of time tracking the changes in its luminosity, and, by proxy, they've seen how the host galaxy has evolved as well. From the ESO:
You can find a larger image here.