Galactic Cirrus between M81 and M82

February 15, 2010 11:56 by scibuff

The image below portraits two galaxies known as M81 (NGC 3031 or Bode’s Galaxy) and M82 (NGC 3034 or the Cigar Galaxy). M81 is one of the most striking examples of a grand design spiral galaxy, with near perfect arms spiraling into the very center. M82 is five times as bright as the whole Milky Way and one hundred times as bright as our galaxy’s center. Tidal forces caused by gravity have deformed this galaxy, a process that started about 100 million years ago. The interaction between the galaxies has caused star formation in M82 to increase 10 fold compared to “normal” galaxies.

M81 and M82

170 minute black and white image of M81 and M82 - Credit:

The inverted image (below) reveals much more that meets the eye. The wispy tendrils seen in the inverted and stretched image are known as Galactic Cirrus. They are high galactic latitude nebulae that are illuminated not by a single star (as most nebula in the plane of the Galaxy are) but by the energy from the integrated flux of all the stars in the Milky Way.  These nebulae clouds, an important component of the Interstellar Medium, are composed of dust particles, hydrogen and carbon monoxide and other elements.

Inverted image of M81 and M82 showing the Galactic Cirrus between the galaxies

Inverted image of M81 and M82 showing the Galactic Cirrus between the galaxies - Credit:

Galactic Cirrus was first found in plates in the Palomar Sky Survey in the mid 1960’s. Alan Sandage investigated them further in 1975 while working with the Palomar 1.2m Schmidt Telescope. The surface brightness of these structures is about 25 mag. or even fainter, which makes them extremely hard to capture with most amateur equipment.

The galaxy group, consisting of M81, M82, NGC 3077 and NGC 2976, is the nearest galaxy group to our own local group (which contains the Milky Way, Magellanic Clouds, M33, and the M31 – M32 – M110 system). At 12 million light years distance, the nearby proximity of galaxies M81 and M82 makes them one of the most spectacular sights in the spring sky.

– The images used in this post have been taken by Alvin Jeng during a test run of the Lightbuckets’ LB0002 – a 0.2m Newtonian Astrograph.

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