Sprial Galaxy


Jaspal Chadha


Imaged using Skywatcher Espirt 100ed telescope
Qsi 690 ccd
LRGB 2 x 300 seconds each filter

The Fireworks Galaxy (NGC 6946 or Arp 29) is an intermediate spiral galaxy of about 75 thousand light-years across, located just some 22.5 million light-years away, on the border between the northern constellations of Cepheus and Cygnus (the Swan). It is moving away from us at approximately 40 kilometers per second.

The center of the Fireworks galaxy is home to a nuclear starburst, in fact, this galaxy is undergoing a tremendous burst of star formation with no obvious cause. In many cases spirals light up when interacting with another galaxy, but this galaxy appears relatively isolated in space. An explanation for the high star formation rate is the recent accretion of many primordial low-mass neutral hydrogen clouds from the surrounding region.

NGC 6946 is called the “Fireworks Galaxy†because so many supernovae have been spotted there in the last hundred years. Actually, nine supernovae (SN 1917A, SN 1939C, SN 1948B, SN 1968D, SN 1969P, SN 1980K, SN 2002hh, SN 2004et, and SN 2008S) have been observed in the galaxy’s spiral arms. With this number of supernovae, NGC 6946 is leading the statistics, just one supernova more than follow-up galaxy the Southern Pinwheel (Messier 83). By comparison, the average rate for supernovae in the Milky Way is about 1 per century.