Messier 81 or Bode’s Galaxy is a spiral galaxy 12 million light years away in Ursa Major. It is a favorite target for both professional astronomers who study its active galactic nucleus harboring a 70 million solar mass super massive black hole, and amateur astronomers who take advantage of the large size and brightness for both visual observing and astroimaging.
Back in 2007 I took my first image of M81. I was just thrilled to be able to take an exposure longer than 1 minute and capture any detail with round stars! In under 10 years with improvement in equipment and processing techniques, much more information about the structure of this galaxy is now appreciated. In my recently completed image of M81 (full res version can be found on the flickr site- see link to astroimaging) you can see not only Arps’s loop, Holmberg IX galaxy but also some very interesting nuclear structure! This is not processing artifact folks. I have not seen this on any published image thus far and wonder what physical properties give rise to them! We have come to assume that galactic nuclei in visible light are just bright blobs of gas, but clearly this is incorrect!
Image taken in 2007 with a 10″ newtonian and SBIG ST8XE camera
M81 just completed. 10″RC and SBIG STXL6303E. Larger arrows point to the now appreciated “Arp’s loop”. This is a loop of gas emanating from the galactic disc but recently at least some of this is believed to exist in our galaxy as “galactic cirrus”. Halton Arp was an astronomer who catalogued interacting galaxies and galaxies with unusual structure and features. The smaller hatched arrow points to Holmberg IX, a dwarf irregular satellite galaxy of M81 formed only 200 million years ago, the youngest nearby galaxy!
Arrows point to peculiar nuclear structure! The arrow closer to the center points to a strange vertical projection of dust toward the center of the nucleus with a round knob-like top! What is it and what causes it? Who says imaging is not science!
