Spiral galaxy M81 in Ursa Major
author: R.Gendler/Novapix
reference: a-gax30-31050
Image Size 300 DPI: 28 * 20 cm
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.