Messier 83 (also known as the Southern Pinwheel Galaxy, M83 or NGC 5236) is an intermediate spiral galaxy approximately 15 million light-years away in the constellation Hydra. It is one of the closest and brightest barred spiral galaxies in the sky, making it visible with binoculars. Six Supernovae (SN 1923A, SN 1945B, SN 1950B, SN 1957D, SN 1968L and SN 1983N) have been observed in M83.
On 16 June 2008 NASA's Galaxy Evolution Explorer project reported finding large numbers of new stars in the outer reaches of the galaxy. It had hitherto been thought that these areas lacked the materials necessary for star formation.