M81 Group

The M81 Group is a galaxy group in the constellations Ursa Major and Camelopardalis that includes the galaxies Messier 81 and Messier 82, as well as several other galaxies with high apparent brightnesses. The approximate center of the group is located at a distance of 3.6 Mpc, making it one of the nearest groups to the Local Group. The group is estimated to have a total mass of (1.03 ± 0.17).
The M81 Group, the Local Group, and other nearby groups all lie within the Virgo Supercluster (i.e. the Local Supercluster).

Members

The table below lists galaxies that have been identified as associated with the M81 Group by I. D. Karachentsev.

Note that the object names used in the above table differ from the names used by Karachentsev. NGC, IC, UGC, and PGC numbers have been used in many cases to allow for easier referencing.

Interactions within the group

Messier 81, Messier 82, and NGC 3077 are all strongly interacting with each other. Observations of the 21-centimeter hydrogen line indicate how the galaxies are connected.
The gravitational interactions have stripped some hydrogen gas away from all three galaxies, leading to the formation of filamentary gas structures within the group. Bridges of neutral hydrogen have been shown to connect M81 with M82 and NGC 3077. Moreover, the interactions have also caused some interstellar gas to fall into the centers of Messier 82 and NGC 3077, which has led to strong starburst activity (or the formation of many stars) within the centers of these two galaxies. Computer simulations of tidal interactions have been used to show how the current structure of the group could have been created.

Gallery

The mysteries of UGC 8201.jpg, Galaxy UGC 8201 is a dwarf irregular galaxy member of the M81 galaxy group.
M81+M82-and other galaxies.jpg, Amateur picture Messier 81 + 82 and NGC 3077 all of the M81 group, 33 frames stacked of 1 minute each.
Image:M81m82 galex f.jpg, The spiral galaxies Messier 81 and 82 and the dwarf galaxy Holmberg IX from GALEX
Image:M81 wide Galex.jpg, Close up view of Messier 81 from GALEX
Image:Messier81 highres.jpg, The spiral galaxy Messier 81 from Spitzer Space Telescope
Image:Ssc2003-06c.jpg, The spiral galaxy Messier 81 from Spitzer Space Telescope
Image:M82 HST ACS 2006-14-a-large web.jpg, Starburst galaxy Messier 82 from Hubble Space Telescope
Image:NGC2403 3.6 5.8 8.0 microns spitzer.png, NGC 2403 in mid-infrared view, combining the 3.6, 5.8 and 8.0 μm bands of the Spitzer Space Telescope
Image:NGC2403 3.6 8.0 24 microns spitzer.png, NGC 2403 in Mid-infrared view, combining the 3.6, 8.0 and 24 μm bands of the Spitzer Space Telescope
Image:NGC 2403HST.jpg, NGC 2403 from Hubble Space Telescope
Image:NGC 2403HSTSN.jpg, NGC 2403 from Hubble Space Telescope illustrated
Image:Galaxy-NGC-2403-with-SN2004DJ.jpeg, Supernova SN2004DJ in the spiral galaxy NGC 2403
Image:NGC2403-SN2004dj.jpg, Supernova 2004dj in NGC 2403
Image:NGC 4236 I FUV g2006.jpg, NGC 4236 from GALEX
Image:NGC 2366HST.jpg, NGC 2366 from Hubble Space Telescope
Image:NGC 2976SSTFull.jpg, Galaxy NGC 2976 from Spitzer Space Telescope in infrared
Image:NGC2976.jpg, Galaxy NGC 2976 from an amateur Astronomer
Image:NGC 4605 GALEX WikiSky.jpg, Galaxy NGC 4605 from GALEX
Image:Ngc2363HST.jpg, NGC 2363 from Hubble Space Telescope
Image:NGC 2537 I FUV g2006.jpeg, NGC 2537 from GALEX
Image:Holmberg IISST.jpg, Holmberg II from Spitzer Space Telescope in infrared
Image:M81DwarBSST.jpg, UGC 5423 / M81 dwarf B from Spitzer Space Telescope in infrared
Image:NGC 3077 2MASS.jpg, NGC 3077 from 2MASS
Image:IC 2574 Hubble WikiSky.jpg, IC 2574

See also

* UGC 5497

References

External links

M81 Group @ SEDS


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Virgo Supercluster
Galaxy clusters