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M81 Group

{{short description|Galaxy group in Ursa Major and Camelopardalis}}

{{Galaxy cluster

| name = M81 Group

| image = 300px

| epoch=J2000

| ra=

| dec=

| constellation = Ursa Major/Camelopardalis

| member_no = 34

| brightest_member = M81 (pictured)

| other_names = NGC 3031 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.{{cite journal

| author=I. D. Karachentsev

| title=The Local Group and Other Neighboring Galaxy Groups

| journal=Astronomical Journal

| date=2005

| volume=129

| issue=1

| pages=178–188

| bibcode=2005AJ....129..178K | doi = 10.1086/426368

|arxiv = astro-ph/0410065 | s2cid=119385141

}} 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){{e|12}}{{Solar mass|link=y}}.{{cite journal

| author=Karachentsev, I. D.

| author2=Kashibadze, O. G.

| title=Masses of the local group and of the M81 group estimated from distortions in the local velocity field

| journal=Astrophysics

| date=2006

| volume=49

| issue=1

| pages=3–18

| bibcode=2006Ap.....49....3K | doi = 10.1007/s10511-006-0002-6

| s2cid=120973010

}}

The M81 Group, the Local Group, and other nearby groups all lie within the Virgo Supercluster (i.e. the Local Supercluster).{{cite journal

| author= R. B. Tully

| title=The Local Supercluster

| journal=Astrophysical Journal

| date=1982

| volume=257

| pages=389–422

| bibcode=1982ApJ...257..389T | doi = 10.1086/159999

| doi-access=free

}}

Members

{{more references needed|section|date=December 2024}}

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

{{clear}}

class="wikitable sortable" style="text-align:center;border-collapse:collapse;" cellpadding="2"

|+Members of the M81 Group

style="background:#efefef;" | Name

! style="background:#efefef;" | Type{{cite web

| title=NASA/IPAC Extragalactic Database

| work=Results for various galaxies

| url=https://web.archive.org/web/20080509/http://nedwww.ipac.caltech.edu/

| access-date=2007-02-09}}

! style="background:#efefef;" | R.A. (J2000)

! style="background:#efefef;" | Dec. (J2000)

! style="background:#efefef;" | Redshift (km/s)

! style="background:#efefef;" | Apparent Magnitude

Arp's Loop{{cn|date=December 2024}}

|

| {{RA|09|57|32.6}}

| {{DEC|+69|17|00}}

| 99

| 16.1

DDO 78{{cn|date=December 2024}}

| Im

| {{RA|10|26|27.4}}

| {{DEC|+67|39|16}}

| 55 ± 10

| 15.8

F8D1{{cn|date=December 2024}}

| dE

| {{RA|09|44|47.1}}

| {{DEC|+67|26|19}}

|

| 13.9

FM1{{cn|date=December 2024}}

| dSph

| {{RA|09|45|10.0}}

| {{DEC|+68|45|54}}

|

| 17.5

HIJASS J1021+6842{{cn|date=December 2024}}

|

| {{RA|10|21|00.0}}

| {{DEC|+68|42|00}}

| 46

| 20

HS 117{{cn|date=December 2024}}

| I

| {{RA|10|21|25.2}}

| {{DEC|+71|06|51}}

| -37

| 16.5

Holmberg I{{cn|date=December 2024}}

| IAB(s)m

| {{RA|09|40|32.3}}

| {{DEC|+71|10|56}}

| 139 ± 0

| 13.0

Holmberg II

| Im

| {{RA|08|19|05.0}}

| {{DEC|+70|43|12}}

| 142 ± 1

| 11.1

Holmberg IX

| Im

| {{RA|09|57|32.0}}

| {{DEC|+69|02|45}}

| 46 ± 6

| 14.3

IC 2574

| SAB(s)m

| {{RA|10|28|23.5}}

| {{DEC|+68|24|44}}

| 57 ± 2

| 13.2

IKN

|

| {{RA|10|08|05.9}}

| {{DEC|+68|23|57}}

|

| 17.0

KKH 57

| dSph

| {{RA|10|00|16.0}}

| {{DEC|+63|11|06}}

|

| 18.5

Messier 81

| SA(s)ab

| {{RA|09|55|33.2}}

| {{DEC|+69|03|55}}

| -34 ± 4

| 6.9

Messier 81 Dwarf A

| I

| {{RA|08|23|56.0}}

| {{DEC|+71|01|45}}

| 113 ± 0

| 16.5

Messier 82

| I0

| {{RA|09|55|52}}

| {{DEC|+69|40|47}}

| 203 ± 4

| 9.3

NGC 2366

| IB(s)m

| {{RA|07|28|54.7}}

| {{DEC|+69|12|57}}

| 80 ± 1

| 11.4

NGC 2403

| SAB(s)cd

| {{RA|07|36|51.4}}

| {{DEC|+65|36|09}}

| 131 ± 3

| 8.9

NGC 2976

| SAc pec

| {{RA|09|47|15.5}}

| {{DEC|+67|54|59}}

| 3 ± 5

| 10.8

NGC 3077

| I0 pec

| {{RA|10|03|19.1}}

| {{DEC|+68|44|02}}

| 14 ± 4

| 10.6

NGC 4236

| SB(s)dm

| {{RA|12|16|42}}

| {{DEC|+69|27|45}}

| 0 ± 4

| 10.1

PGC 28529

| Im

| {{RA|09|53|48.5}}

| {{DEC|+68|58|08}}

| -40

| 17.1

PGC 28731

| dE

| {{RA|09|57|03.1}}

| {{DEC|+68|35|31}}

| -135 ± 30

| 15.6

PGC 29231

| dE

| {{RA|10|04|41.1}}

| {{DEC|+68|15|22}}

|

| 16.7

PGC 31286

| dSph

| {{RA|10|34|29.8}}

| {{DEC|+66|00|30}}

|

| 16.7

PGC 32667

| Im

| {{RA|10|52|57.1}}

| {{DEC|+69|32|58}}

| 116 ± 1

| 14.9

UGC 4459

| Im

| {{RA|08|34|07.2}}

| {{DEC|+66|10|54}}

| 20 ± 0

| 14.5

UGC 4483

|

| {{RA|08|37|03.0}}

| {{DEC|+69|46|31}}

| 156 ± 0

| 15.1

UGC 5428

| Im

| {{RA|10|05|06.4}}

| {{DEC|+66|33|32}}

| -129 ± 0

| 18

UGC 5442

| Im

| {{RA|10|07|01.9}}

| {{DEC|+67|49|39}}

| -18 ± 14

| 18

UGC 5692

| Sm

| {{RA|10|30|35.0}}

| {{DEC|+70|37|07.2}}

| 56 ± 3

| 13.5

UGC 6456

| Pec

| {{RA|11|27|59.9}}

| {{DEC|+78|59|39}}

| -103 ± 0

| 14.5

UGC 7242

| Scd

| {{RA|12|14|08.4}}

| {{DEC|+66|05|41}}

| 68 ± 2

| 14.6

UGC 8201

| Im

| {{RA|13|06|24.9}}

| {{DEC|+67|42|25}}

| 31 ± 0

| 12.8

UGCA 133

| dSph

| {{RA|07|34|11.4}}

| {{DEC|+66|53|10}}

|

| 15.6

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.{{cite journal

| author=M. S. Yun

| author2=P. T. P. Ho

| author3=K. Y. Lo

| title=A high-resolution image of atomic hydrogen in the M81 group of galaxies

| journal=Nature

| date=1994

| volume=372

| pages=530–532

| bibcode=1994Natur.372..530Y | doi = 10.1038/372530a0

| pmid=7990925

| issue=6506

| s2cid=4369085

}} Observations of the 21-centimeter hydrogen line indicate how the galaxies are connected.{{cite journal

|last1=Chynoweth

|first1=Katie M.

|display-authors=etal

|title=Neutral Hydrogen Clouds in the M81/M82 Group

|journal=The Astronomical Journal

|date=2008

|volume=135

|issue=2008 June

|pages=1983–1992

|doi=10.1088/0004-6256/135/6/1983|arxiv=0803.3631

|bibcode=2008AJ....135.1983C

|s2cid=4490764

}}

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.{{cite journal |last1=Hulst

|first1=J. M. van der

|title=The Structure and Kinematics of the Neutral Hydrogen Bridge Between M 81 and NGC 3077

|journal=Astronomy and Astrophysics

|date=1978

|volume=75

|issue=1–2

|pages=97–111}} 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.{{cite book

|last1=Yun |first1=M. S.

|chapter=Tidal Interactions in M81 Group

|title=Galaxy Interactions at Low and High Redshift

|date=1999

|volume=186

|page=81

|doi=10.1007/978-94-011-4665-4_18

|bibcode=1999IAUS..186...81Y

|isbn=978-0-7923-5833-6

|ref=1999IAUS..186...81Y}}

Gallery

The mysteries of UGC 8201.jpg|Galaxy UGC 8201 is a dwarf irregular galaxy member of the M81 galaxy group.{{cite web|title=The mysteries of UGC 8201|url=http://www.spacetelescope.org/images/potw1510a/|access-date=18 June 2015}}

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

References

{{Reflist}}

External links

  • [http://messier.seds.org/more/m081gr.html M81 Group @ SEDS]
  • [http://www.atlasoftheuniverse.com/galgrps/m81.html M81 Group from An Atlas of The Universe]

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