Spiral galaxy M81 in the Great Bear - Spiral galaxy M81 in Ursa Major -...

Spiral galaxy M81 in the Great Bear - Spiral galaxy M81 in Ursa Major - The spiral galaxy M81 is located 12 million years ago - light from Earth. Its arms are home to star-forming regions while its core is surrounded by much older yellow stars. An irregular dwarf galaxy, PGC 28757 (Holmberg IX), is visible at the top of the picture. M81 is the brightest member of the nearby galactic group called the M81 group. This group contains at least 25 other members including the peculiar starburst galaxy M82, the peculiar galaxy NGC 3077 and many dwarfs galaxies. The core galaxies of the group (M81, M82, NGC 3077, NGC 2976) are strongly interacting and are all imbedded within a large and extended molecular gas cloud. The Dwarf irregular Holmberg IX (seen above M81 in the image) most likely condensed from tidal debri existing between M81 and M82. M81 has the distinction of being the nearest spiral galaxy to have an active galactic nucleus (AGN). AGN galaxies are luminous galaxies that demonstrate much of their luminosity as nonstellar emission arising from their nucleus. The modern interpretation for the unusual energy output is the presence of a super massive black hole which consumes infalling matter from a rotating accretion disk in the galaxy's center