M66 is a spiral galaxy, and is part of the Leo triplet, a group of three interacting galaxies in the constellation Leo (pictured below).  The sixty sixth entry in Charles Messier’s famous catalogue of Things That Aren’t Comets, it has an unusual asymmetric shape, with spiral arms arcing over the main disc and an off-centre nucleus.  This is probably a result of gravitational interaction with the other two members of the group, which has also resulted in unusually high rates of new star formation.  The galaxy has a remarkably high rate of supernova explosions, having hosted three between 1989 and 2009.

For more information, read the press release here.

All images courtesy of NASA, ESA and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration. Acknowledgement: Davide De Martin and Robert Gendler