M81 Group

Last updated
M81 Group
Messier 81 HST.jpg
Observation data (Epoch J2000)
Constellation(s) Ursa Major/Camelopardalis
Brightest member M81 [1] (pictured)
Number of galaxies34 [1]
Other designations
NGC 3031 Group
See also: Galaxy group, Galaxy cluster, List of galaxy groups and clusters

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. [1] 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. [1] The group is estimated to have a total mass of (1.03 ± 0.17)×1012 M☉. [2] The M81 Group, the Local Group, and other nearby groups all lie within the Virgo Supercluster (i.e. the Local Supercluster). [3]

Contents

Members

The table below lists galaxies that have been identified as associated with the M81 Group by I. D. Karachentsev. [1]

Members of the M81 Group
Name Type [4] R.A. (J2000) [4] Dec. (J2000) [4] Redshift (km/s) [4] Apparent Magnitude [4]
Arp's Loop 09h 57m 32.6s+69° 17′ 00″9916.1
DDO 78 Im10h 26m 27.4s+67° 39′ 16″55 ± 1015.8
F8D1 dE09h 44m 47.1s+67° 26′ 19″13.9
FM1 dSph09h 45m 10.0s+68° 45′ 54″17.5
HIJASS J1021+6842 10h 21m 00.0s+68° 42′ 00″4620
HS 117 I10h 21m 25.2s+71° 06′ 51″-3716.5
Holmberg I IAB(s)m09h 40m 32.3s+71° 10′ 56″139 ± 013.0
Holmberg II Im08h 19m 05.0s+70° 43′ 12″142 ± 111.1
Holmberg IX Im09h 57m 32.0s+69° 02′ 45″46 ± 614.3
IC 2574 SAB(s)m10h 28m 23.5s+68° 24′ 44″57 ± 213.2
IKN 10h 08m 05.9s+68° 23′ 57″17.0
KKH 57 dSph10h 00m 16.0s+63° 11′ 06″18.5
Messier 81 SA(s)ab09h 55m 33.2s+69° 03′ 55″-34 ± 46.9
Messier 81 Dwarf A I08h 23m 56.0s+71° 01′ 45″113 ± 016.5
Messier 82 I009h 55m 52s+69° 40′ 47″203 ± 49.3
NGC 2366 IB(s)m07h 28m 54.7s+69° 12′ 57″80 ± 111.4
NGC 2403 SAB(s)cd07h 36m 51.4s+65° 36′ 09″131 ± 38.9
NGC 2976 SAc pec09h 47m 15.5s+67° 54′ 59″3 ± 510.8
NGC 3077 I0 pec10h 03m 19.1s+68° 44′ 02″14 ± 410.6
NGC 4236 SB(s)dm12h 16m 42s+69° 27′ 45″0 ± 410.1
PGC 28529 Im09h 53m 48.5s+68° 58′ 08″-4017.1
PGC 28731 dE09h 57m 03.1s+68° 35′ 31″-135 ± 3015.6
PGC 29231 dE10h 04m 41.1s+68° 15′ 22″16.7
PGC 31286 dSph10h 34m 29.8s+66° 00′ 30″16.7
PGC 32667 Im10h 52m 57.1s+69° 32′ 58″116 ± 114.9
UGC 4459 Im08h 34m 07.2s+66° 10′ 54″20 ± 014.5
UGC 4483 08h 37m 03.0s+69° 46′ 31″156 ± 015.1
UGC 5428 Im10h 05m 06.4s+66° 33′ 32″-129 ± 018
UGC 5442 Im10h 07m 01.9s+67° 49′ 39″-18 ± 1418
UGC 5692 Sm10h 30m 35.0s+70° 37′ 07.2″56 ± 313.5
UGC 6456 Pec11h 27m 59.9s+78° 59′ 39″-103 ± 014.5
UGC 7242 Scd12h 14m 08.4s+66° 05′ 41″68 ± 214.6
UGC 8201 Im13h 06m 24.9s+67° 42′ 25″31 ± 012.8
UGCA 133 dSph07h 34m 11.4s+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. [5] Observations of the 21-centimeter hydrogen line indicate how the galaxies are connected. [6] The gravitational interactions have stripped some hydrogen gas away from all three galaxies, leading to the formation of filamentary gas structures within the group. [5] Bridges of neutral hydrogen have been shown to connect M81 with M82 and NGC 3077. [6] [7] 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. [5] Computer simulations of tidal interactions have been used to show how the current structure of the group could have been created. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Messier 82</span> Starburst galaxy in the constellation Ursa Major

Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major. It is the second-largest member of the M81 Group, with the D25 isophotal diameter of 12.52 kiloparsecs (40,800 light-years). It is about five times more luminous than the Milky Way and its central region is about one hundred times more luminous. The starburst activity is thought to have been triggered by interaction with neighboring galaxy M81. As one of the closest starburst galaxies to Earth, M82 is the prototypical example of this galaxy type. SN 2014J, a type Ia supernova, was discovered in the galaxy on 21 January 2014. In 2014, in studying M82, scientists discovered the brightest pulsar yet known, designated M82 X-2.

<span class="mw-page-title-main">Pinwheel Galaxy</span> Galaxy in the constellation Ursa Major

The Pinwheel Galaxy is a face-on spiral galaxy located 21 million light-years from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries.

<span class="mw-page-title-main">Messier 61</span> Galaxy in the constellation Virgo

Messier 61 is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet. Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.

<span class="mw-page-title-main">Messier 81</span> Spiral galaxy in the constellation Ursa Major

Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major. It has a D25 isophotal diameter of 29.44 kiloparsecs (96,000 light-years). Because of its relative proximity to the Milky Way galaxy, large size, and active galactic nucleus (which harbors a 70 million M☉ supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for amateur astronomers. In late February 2022, astronomers reported that M81 may be the source of FRB 20200120E, a repeating fast radio burst.

<span class="mw-page-title-main">Sombrero Galaxy</span> Galaxy in the constellation Virgo

The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs, making it slightly bigger in size than the Milky Way.

<span class="mw-page-title-main">Messier 63</span> Spiral galaxy in the constellation Canes Venatici

Messier 63 or M63, also known as NGC 5055 or the seldom-used Sunflower Galaxy, is a spiral galaxy in the northern constellation of Canes Venatici with approximately 400 billion stars. M63 was first discovered by the French astronomer Pierre Méchain, then later verified by his colleague Charles Messier on June 14, 1779. The galaxy became listed as object 63 in the Messier Catalogue. In the mid-19th century, Anglo-Irish astronomer Lord Rosse identified spiral structures within the galaxy, making this one of the first galaxies in which such structure was identified.

<span class="mw-page-title-main">Messier 66</span> Intermediate spiral galaxy in the constellation Leo

Messier 66 or M66, also known as NGC 3627, is an intermediate spiral galaxy in the southern, equatorial half of Leo. It was discovered by French astronomer Charles Messier on 1 March 1780, who described it as "very long and very faint". This galaxy is a member of a small group of galaxies that includes M65 and NGC 3628, known as the Leo Triplet or the M66 Group. M65 and M66 are a common object for amateur astronomic observation, being separated by only 20′.

<span class="mw-page-title-main">NGC 2403</span> Galaxy in the constellation Camelopardalis

NGC 2403 is an intermediate spiral galaxy in the constellation Camelopardalis. It is an outlying member of the M81 Group, and is approximately 8 million light-years distant. It bears a similarity to M33, being about 50,000 light years in diameter and containing numerous star-forming H II regions. The northern spiral arm connects it to the star forming region NGC 2404. NGC 2403 can be observed using 10×50 binoculars. NGC 2404 is 940 light-years in diameter, making it one of the largest known H II regions. This H II region represents striking similarity with NGC 604 in M33, both in size and location in galaxy.

<span class="mw-page-title-main">Messier 94</span> Galaxy in the constellation Canes Venatici

Messier 94 is a spiral galaxy in the mid-northern constellation Canes Venatici. It was discovered by Pierre Méchain in 1781, and catalogued by Charles Messier two days later. Although some references describe M94 as a barred spiral galaxy, the "bar" structure appears to be more oval-shaped. The galaxy has two ring structures.

<span class="mw-page-title-main">Messier 108</span> Galaxy in the constellation Ursa Major

Messier 108 is a barred spiral galaxy about 28 million light-years away from Earth in the northern constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the Earth, this galaxy is seen almost edge-on.

<span class="mw-page-title-main">Sculptor Galaxy</span> Intermediate spiral galaxy in the constellation Sculptor

The Sculptor Galaxy is an intermediate spiral galaxy in the constellation Sculptor. The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.

<span class="mw-page-title-main">NGC 891</span> Galaxy in the constellation Andromeda

NGC 891 is an edge-on unbarred spiral galaxy about 30 million light-years away in the constellation Andromeda. It was discovered by William Herschel on October 6, 1784. The galaxy is a member of the NGC 1023 group of galaxies in the Local Supercluster. It has an H II nucleus.

<span class="mw-page-title-main">NGC 6822</span> Galaxy in the constellation Sagittarius

NGC 6822 is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884, with a six-inch refractor telescope. It is the closest non-satellite galaxy to the Milky Way, but lies just outside its virial radius. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.

<span class="mw-page-title-main">NGC 3077</span> Galaxy in the constellation Ursa Major

NGC 3077 is a small disrupted elliptical galaxy, a member of the M81 Group, which is located in the northern constellation Ursa Major. Despite being similar to an elliptical galaxy in appearance, it is peculiar for two reasons. First, it shows wispy edges and scattered dust clouds that are probably a result of gravitational interaction with its larger neighbors, similar to the galaxy M82. Second, this galaxy has an active nucleus. This caused Carl Seyfert in 1943 to include it in his list of galaxies, which are now called Seyfert Galaxies. However, NGC 3077, though an emission line galaxy, is today no longer classified as a Seyfert galaxy.

<span class="mw-page-title-main">Bubble Nebula (NGC 6822)</span> Nebula in Barnards Galaxy in the constellation Sagittarius

The Bubble Nebula in Barnard's Galaxy has the official designation of Hubble 1925 I as it was the first object recorded in a paper by Hubble 1925. It includes areas of bright H II emission. It is located north-west of the larger Hubble 1925 III.

<span class="mw-page-title-main">NGC 625</span> Galaxy in the constellation of Phoenix

NGC 625 is a dwarf barred spiral galaxy about 12.7 Mly away in the constellation Phoenix. NGC 625 is a member of the Sculptor Group.

<span class="mw-page-title-main">NGC 4236</span> Galaxy in the constellation Draco

NGC 4236 is a barred spiral galaxy located in the constellation Draco.

<span class="mw-page-title-main">SN 2014J</span> Supernova in Messier 82

SN 2014J was a type-Ia supernova in Messier 82 discovered in mid-January 2014. It was the closest type-Ia supernova discovered for 42 years, and no subsequent supernova has been closer as of 2023. The supernova was discovered by chance during an undergraduate teaching session at the University of London Observatory. It peaked on 31 January 2014, reaching an apparent magnitude of 10.5. SN 2014J was the subject of an intense observing campaign by professional astronomers and was bright enough to be seen by amateur astronomers.

<span class="mw-page-title-main">NGC 1084</span> Galaxy in the constellation Eridanus

NGC 1084 is an unbarred spiral galaxy in the constellation Eridanus. It is located at a distance of about 63 million light-years away from the Milky Way. The galaxy was discovered by William Herschel on 10 January 1785. It has multiple spiral arms, which are not well defined. It belongs in the same galaxy group with NGC 988, NGC 991, NGC 1022, NGC 1035, NGC 1042, NGC 1047, NGC 1052 and NGC 1110. This group is in turn associated with the Messier 77 group.

<span class="mw-page-title-main">Local Volume</span>

The Local Volume is a collection of more than 500 galaxies located in an area of the observable universe near us, within a spherical region with a radius of 11 megaparsecs from Earth or up to a radial velocity of redshift of z < 0.002.

References

  1. 1 2 3 4 5 I. D. Karachentsev (2005). "The Local Group and Other Neighboring Galaxy Groups". Astronomical Journal. 129 (1): 178–188. arXiv: astro-ph/0410065 . Bibcode:2005AJ....129..178K. doi:10.1086/426368. S2CID   119385141.
  2. ↑ Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics. 49 (1): 3–18. Bibcode:2006Ap.....49....3K. doi:10.1007/s10511-006-0002-6. S2CID   120973010.
  3. ↑ R. B. Tully (1982). "The Local Supercluster". Astrophysical Journal. 257: 389–422. Bibcode:1982ApJ...257..389T. doi: 10.1086/159999 .
  4. 1 2 3 4 5 "NASA/IPAC Extragalactic Database". Results for various galaxies. Retrieved 2007-02-09.
  5. 1 2 3 M. S. Yun; P. T. P. Ho; K. Y. Lo (1994). "A high-resolution image of atomic hydrogen in the M81 group of galaxies". Nature. 372 (6506): 530–532. Bibcode:1994Natur.372..530Y. doi:10.1038/372530a0. PMID   7990925. S2CID   4369085.
  6. 1 2 Chynoweth, Katie M.; et al. (2008). "Neutral Hydrogen Clouds in the M81/M82 Group". The Astronomical Journal. 135 (2008 June): 1983–1992. arXiv: 0803.3631 . Bibcode:2008AJ....135.1983C. doi:10.1088/0004-6256/135/6/1983. S2CID   4490764.
  7. ↑ Hulst, J. M. van der (1978). "The Structure and Kinematics of the Neutral Hydrogen Bridge Between M 81 and NGC 3077". Astronomy and Astrophysics. 75 (1–2): 97–111.
  8. ↑ Yun, M. S. (1999). "Tidal Interactions in M81 Group". Galaxy Interactions at Low and High Redshift, Proceedings of IAU Symposium. 186: 81. Bibcode:1999IAUS..186...81Y. doi:10.1007/978-94-011-4665-4_18. ISBN   978-0-7923-5833-6.
  9. ↑ "The mysteries of UGC 8201" . Retrieved 18 June 2015.
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