IC 342/Maffei Group

IC 342/Maffei Group
IC 342/Maffei Group
	Maffei 1, one of the brightest galaxies in the group
Observation data (Epoch J2000)
Constellation(s)	Cassiopeia/Camelopardalis/Perseus
Brightest member	IC 342
Number of galaxies	16
Other designations
	IC 342 Group, Maffei 1 Group, LGG 104

Last updated August 06, 2024

The IC 342/Maffei Group (also known as the IC 342 Group or the Maffei 1 Group) corresponds to one or two galaxy groups close to the Local Group. The member galaxies are mostly concentrated around either IC 342 or Maffei 1, which would be the brightest two galaxies in the group.^[1] The group is part of the Virgo Supercluster.^[2] However, recent studies have found that the two subgroups are unrelated; while the IC 342 group is the nearest galaxy group to the Milky Way, the Maffei 1 group is several times farther away, and is not gravitationally bound to the IC 342 group.^[3]^[4]

Members

The table below lists galaxies that have been identified as associated with the IC342/Maffei 1 Group by I. D. Karachentsev.^[1]^[5] Note that Karachentsev divides this group into two subgroups centered around IC 342 and Maffei 1.

**Members of the IC 342 Subgroup**
Name	Type ^[6]	R.A. (J2000)^[6]	Dec. (J2000)^[6]	Redshift (km/s)^[6]	Apparent Magnitude ^[6]
Camelopardalis A	Irr	04^h 26^m 16.3^s	+72° 48′ 21″	–46 ± 1	14.8
Camelopardalis B	Irr	04^h 53^m 07.1^s	+67° 05′ 57″	77	16.1
IC 342	SAB(rs)cd	03^h 46^m 48.5^s	+68° 05′ 46″	31 ± 3	9.1
KK 35	Irr	03^h 45^m 12.6^s	+67° 51′ 51″	105 ± 1	17.2
KKH 22 ^[5]	dSph	03^h 44^m 56.6^s	+72° 03′ 52″	30 ± 10	15.3
NGC 1560	SA(s)d	04^h 32^m 49.1^s	+71° 52′ 59″	–36 ± 5	12.2
NGC 1569	Sbrst	04^h 30^m 49.1^s	+64° 50′ 52,6″	–104 ± 4	11.2
UGCA 86	Im	03^h 59^m 50.5^s	+67° 08′ 37″	67 ± 4	13.5
UGCA 92	Im	04^h 32^m 04.9^s	+63° 36′ 49.0″	–99 ± 5	13.8
UGCA 105	Im	05^h 14^m 15.3^s	+62° 34′ 48″	111 ± 5	13.9

**Members of the Maffei 1 Subgroup**
Name	Type ^[6]	R.A. (J2000)^[6]	Dec. (J2000)^[6]	Redshift (km/s)^[6]	Apparent Magnitude ^[6]
Dwingeloo 1	SB(s)cd	02^h 56^m 51.9^s	+58° 54′ 42″	110	8.3
Dwingeloo 2	Im	02^h 54^m 08.5^s	+59° 00′ 19″	94 ± 1	20.5
KKH 11	dE	02^h 24^m 34.2^s	+56° 00′ 43″	310	16.2
KKH 12	Irr	02^h 27^m 26.9^s	+57° 29′ 16″	70	17.8
Maffei 1	S0 pec	02^h 36^m 35.4^s	+59° 39′ 19″	13 ± 22	11.4
Maffei 2	SAB(rs)bc	02^h 41^m 55.1^s	+59° 36′ 15″	–17 ± 5	16.0
MB 1	SAB(s)d	02^h 35^m 36.5^s	+59° 22′ 43″	190 ± 1	20.5
MB 3	dSph	02^h 55^m 42.7^s	+58° 51′ 37″	59 ± 1	17.33

Additionally, KKH 37 is listed as possibly being a member of the IC 342 Subgroup, and KKH 6 is listed as possibly being a member of the Maffei 1 Subgroup.^[1]

Maffei 1 and Maffei 2 are visible in this image.

Foreground dust obscuration

As seen from Earth, the group lies near the plane of the Milky Way (a region sometimes called the Zone of Avoidance). Consequently, the light from many of the galaxies is severely affected by dust obscuration within the Milky Way. This complicates observational studies of the group, as uncertainties in the dust obscuration also affect measurements of the galaxies' luminosities and distances as well as other related quantities.^[1]^[7]

Moreover, the galaxies within the group have historically been difficult to identify. Many galaxies have only been discovered using late 20th century astronomical instrumentation. For example, while many fainter, more distant galaxies, such as the galaxies in the New General Catalogue, were already identified visually by the end of the nineteenth century,^{[ citation needed ]} Maffei 1 and Maffei 2 were only discovered in 1968 using infrared photographic images of the region.^[8] Furthermore, it is difficult to determine whether some objects near IC 342 or Maffei 1 are galaxies associated with the IC 342/Maffei Group or diffuse foreground objects within the Milky Way that merely look like galaxies. For example, the objects MB 2 and Camelopardalis C were once thought to be dwarf galaxies in the IC 342/Maffei Group but are now known to be objects within the Milky Way.^[9]

Group formation and possible interactions with the Local Group

Since the IC 342/Maffei Group and the Local Group are located physically close to each other, the two groups may have influenced each other's evolution during the early stages of galaxy formation. An analysis of the velocities and distances to the IC 342/Maffei Group as measured by M. J. Valtonen and collaborators suggested that IC 342 and Maffei 1 were moving faster than what could be accounted for in the expansion of the universe. They therefore suggested that IC 342 and Maffei 1 were ejected from the Local Group after a violent gravitational interaction with the Andromeda Galaxy during the early stages of the formation of the two groups.^[10]

However, this interpretation is dependent on the distances measured to the galaxies in the group, which in turn is dependent on accurately measuring the degree to which interstellar dust in the Milky Way obscures the group.^[7]^[11] More recent observations have demonstrated that the dust obscuration may have been previously overestimated, so the distances may have been underestimated. If these new distance measurements are correct, then the galaxies in the IC 342/Maffei Group appear to be moving at the rate expected from the expansion of the universe, and the scenario of a collision between the IC 342/Maffei Group and the Local Group would be implausible.^[11]

Related Research Articles

The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly 3 megaparsecs (10 million light-years; 9×10¹⁹ kilometres), and a total mass of the order of 2×10¹² solar masses (4×10⁴² kg). It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about 800 kiloparsecs (3×10^⁶ ly; 2×10¹⁹ km) and are moving toward one another with a velocity of 123 km/s. The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies.

IC 10 is an irregular galaxy in the constellation Cassiopeia. It was discovered by Lewis Swift in 1887 and in 1935 Nicholas Mayall became the first to suggest that the object is extragalactic. Edwin Hubble suspected it might belong to the Local Group of galaxies, but its status remained uncertain for decades. The radial velocity of IC 10 was measured in 1962, and it was found to be approaching the Milky Way at approximately 350 km/s, strengthening the evidence for its membership in the Local Group. Its membership in the group was finally confirmed in 1996 by direct measurements of its distance based on observations of Cepheids; most estimates place the galaxy 2–3 million light years from Earth, with some estimates ranging from 1.5–4.5 million light years. Despite its closeness, the galaxy is rather difficult to study because it lies near the plane of the Milky Way and is therefore heavily obscured by interstellar matter.

Centaurus A is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type and distance. It is the closest radio galaxy to Earth, as well as the closest BL Lac object, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth-brightest in the sky, making it an ideal amateur astronomy target. It is only visible from the southern hemisphere and low northern latitudes.

Dwingeloo 1 is a barred spiral galaxy about 10 million light-years away from the Earth, in the constellation Cassiopeia. It lies in the Zone of Avoidance and is heavily obscured by the Milky Way. The size and mass of Dwingeloo 1 are comparable to those of Triangulum Galaxy.

Dwingeloo 2 is a small irregular galaxy discovered in 1996 and located about 10 million light-years away from the Earth. Its discovery was a result of the Dwingeloo Obscured Galaxy Survey (DOGS) of the Zone of Avoidance using the Dwingeloo Radio Observatory. Dwingeloo 2 is a companion galaxy of Dwingeloo 1.

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.

The Centaurus A/M83 Group is a complex group of galaxies in the constellations Hydra, Centaurus, and Virgo. The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9 Mly, is centered on Centaurus A, a nearby radio galaxy. The M83 Subgroup, at a distance of 14.9 Mly, is centered on the Messier 83 (M83), a face-on spiral galaxy.

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.

NGC 1569 is a dwarf irregular galaxy in Camelopardalis. The galaxy is relatively nearby and consequently, the Hubble Space Telescope can easily resolve the stars within the galaxy. The distance to the galaxy was previously believed to be only 2.4 Mpc. However, in 2008 scientists studying images from Hubble calculated the galaxy's distance at nearly 11 million light-years away, about 4 million light-years farther than previously thought, meaning it is a member of the IC 342 group of galaxies.

IC 1613 is an irregular dwarf galaxy, visible in the constellation Cetus near the star 26 Ceti. It was discovered in 1906 by Max Wolf, and is approaching Earth at 234 km/s.

IC 342 is an intermediate spiral galaxy in the constellation Camelopardalis, located relatively close to the Milky Way. Despite its size and actual brightness, its location behind dusty areas near the galactic equator makes it difficult to observe, leading to the nickname "The Hidden Galaxy", though it can readily be detected even with binoculars. If the galaxy were not obscured, it would be visible by naked eye. The dust makes it difficult to determine its precise distance; modern estimates range from about 7 million light-years (Mly) to about 11 Mly. The galaxy was discovered by William Frederick Denning in 1892. It is one of the brightest in the IC 342/Maffei Group, one of the closest galaxy groups to the Local Group. Edwin Hubble first thought it to be in the Local Group, but it was later determined not to be a member.

NGC 4945 (also known as Caldwell 83) is a barred spiral galaxy in the constellation Centaurus, visible near the star Xi Centauri. The galaxy was discovered by James Dunlop in 1826 and is thought to be similar to the Milky Way Galaxy, although X-ray observations show that NGC 4945 has an unusual energetic Seyfert 2 nucleus that might house a supermassive black hole. Around the nucleus of the galaxy, there is a dense disk of dust and gas, along with many dense star clusters. This object has an estimated mass of 1.4+1.4
−0.7×10¹¹ M_☉.

NGC 5253 is an irregular galaxy in the constellation Centaurus. It was discovered by William Herschel on 15 March 1787.

UGCA 86 is a Magellanic spiral galaxy. It was first thought to be part of the Local Group, but after the brightest stars in the galaxy were observed, it became clear that it was located in the IC 342/Maffei Group. UGCA 86 is thought to be a satellite galaxy of IC 342, however the separation between the two galaxies is over 50% larger than the distance between the Milky Way and the Magellanic Clouds.

<span class="mw-page-title-main">Maffei 1</span> Galaxy in the constellation Cassiopeia

Maffei 1 is a massive elliptical galaxy in the constellation Cassiopeia. Once believed to be a member of the Local Group of galaxies, it is now known to belong to a separate group, the IC 342/Maffei Group. It was named after Paolo Maffei, who discovered it and the neighboring Maffei 2 in 1967 via their infrared emissions.

<span class="mw-page-title-main">Maffei 2</span> Galaxy in the constellation Cassiopeia

Maffei 2 is an intermediate spiral galaxy about 10 million light-years away in the constellation Cassiopeia. Maffei 2 and Maffei 1 were both discovered by Paolo Maffei in 1968 from their infrared emission. Maffei 2 lies in the Zone of Avoidance and is about 99.5% obscured by the Milky Way's foreground dust clouds, and as a result is barely detectable at optical wavelengths. It had been suggested soon after its discovery that Maffei 2 may be a member of the Local Group, but it is now thought to be a member of another nearby group, the IC 342/Maffei Group, the galaxy group that is the closest to the Local Group.

The Local Sheet in astronomy is a nearby extragalactic region of space where the Milky Way, the members of the Local Group and other galaxies share a similar peculiar velocity. This region lies within a radius of about 7 Mpc (23 Mly), 0.46 Mpc (1.5 Mly) thick, and galaxies beyond that distance show markedly different velocities. The Local Group has only a relatively small peculiar velocity of 66 km⋅s⁻¹ with respect to the Local Sheet. Typical velocity dispersion of galaxies is only 40 km⋅s⁻¹ in the radial direction. Nearly all nearby bright galaxies belong to the Local Sheet. The Local Sheet is part of the Local Volume and is in the Virgo Supercluster. The Local Sheet forms a wall of galaxies delineating one boundary of the Local Void.

MB 3 is a dwarf spheroidal galaxy discovered in 1997 and located about 10 million light-years away from the Earth. It was discovered during an optical survey of the IC 342/Maffei group to which the galaxy is a member. MB3 is a companion galaxy of Dwingeloo 1 and situated in the Zone of Avoidance. MB 3 is thought to be a member of the IC 342/Maffei Group, a galaxy group adjacent to the Local Group.

NGC 1560, also known as IC 2062, is an 11th-magnitude spiral galaxy, in the IC 342/Maffei Group. It was discovered by Wilhelm Tempel on August 1, 1883.

References

1 2 3 4 5 6 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.
↑ R. B. Tully (1982). "The Local Supercluster". Astrophysical Journal. 257: 389–422. Bibcode:1982ApJ...257..389T. doi: 10.1086/159999 .
↑ Tikhonov, N. A.; Galazutdinova, O. A. (2018). "Does the IC 342/Maffei Galaxy Group Really Exist?". Astrophysical Bulletin. 73 (3): 279–292. Bibcode:2018AstBu..73..279T. doi:10.1134/S1990341318030021. S2CID 126018966.
↑ Anand, Gagandeep S.; Tully, R. Brent; Rizzi, Luca; Karachentsev, Igor D. (2019). "The Distance and Motion of the Maffei Group". The Astrophysical Journal. 872 (1): L4. arXiv: 1901.05981 . Bibcode:2019ApJ...872L...4A. doi: 10.3847/2041-8213/aafee6 . S2CID 119227716.
1 2 Karachentsev, Igor D.; Makarova, Lidia N.; Brent Tully, R.; Anand, Gagandeep S.; Rizzi, Luca; Shaya, Edward J.; Afanasiev, Viktor L. (2020). "KKH 22, the first dwarf spheroidal satellite of IC 342". Astronomy & Astrophysics. 638: A111. arXiv: 2005.03132 . Bibcode:2020A&A...638A.111K. doi:10.1051/0004-6361/202037993. S2CID 218538458.
1 2 3 4 5 6 7 8 9 10 "NASA/IPAC Extragalactic Database". Results for various galaxies. Retrieved 2006-12-30.
1 2 R. J. Buta; M. L. McCall (1999). "The IC 342/Maffei Group Revealed". Astrophysical Journal Supplement Series. 124 (1): 33–93. Bibcode:1999ApJS..124...33B. doi: 10.1086/313255 .
↑ P. Maffei (1968). "Infrared Object in the Region of IC 1895". Publications of the Astronomical Society of the Pacific. 80 (476): 618–621. Bibcode:1968PASP...80..618M. doi: 10.1086/128698 .
↑ I. D. Karachentsev; M. E. Sharina; A. E. Dolphin; E. K. Grebel (2003). "Distances to nearby galaxies around IC 342". Astronomy and Astrophysics. 408 (1): 111–118. Bibcode:2003A&A...408..111K. doi: 10.1051/0004-6361:20030912 .
↑ M. J. Valtonen; G. G. Byrd; M. L. McCall; K. A. Innanen (1993). "A revised history of the Local Group and a generalized method of timing". Astronomical Journal. 105: 886–893. Bibcode:1993AJ....105..886V. doi:10.1086/116480.
1 2 R. L. Fingerhut; H. Lee; M. L. McCall; M. G. Richer (2007). "The Extinction and Distance of Maffei 2 and a New View of the IC 342/Maffei Group". Astrophysical Journal. 655 (2): 814–830. arXiv: astro-ph/0610044 . Bibcode:2007ApJ...655..814F. doi:10.1086/509862. S2CID 18405597.

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[karachentsev2005-1] 1 2 3 4 5 6 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.

[tully1982-2] R. B. Tully (1982). "The Local Supercluster". Astrophysical Journal. 257: 389–422. Bibcode:1982ApJ...257..389T. doi: 10.1086/159999 .

[3] Tikhonov, N. A.; Galazutdinova, O. A. (2018). "Does the IC 342/Maffei Galaxy Group Really Exist?". Astrophysical Bulletin. 73 (3): 279–292. Bibcode:2018AstBu..73..279T. doi:10.1134/S1990341318030021. S2CID 126018966.

[4] Anand, Gagandeep S.; Tully, R. Brent; Rizzi, Luca; Karachentsev, Igor D. (2019). "The Distance and Motion of the Maffei Group". The Astrophysical Journal. 872 (1): L4. arXiv: 1901.05981 . Bibcode:2019ApJ...872L...4A. doi: 10.3847/2041-8213/aafee6 . S2CID 119227716.

[Karachentsev2020-5] 1 2 Karachentsev, Igor D.; Makarova, Lidia N.; Brent Tully, R.; Anand, Gagandeep S.; Rizzi, Luca; Shaya, Edward J.; Afanasiev, Viktor L. (2020). "KKH 22, the first dwarf spheroidal satellite of IC 342". Astronomy & Astrophysics. 638: A111. arXiv: 2005.03132 . Bibcode:2020A&A...638A.111K. doi:10.1051/0004-6361/202037993. S2CID 218538458.

[ned-6] 1 2 3 4 5 6 7 8 9 10 "NASA/IPAC Extragalactic Database". Results for various galaxies. Retrieved 2006-12-30.

[butamccall1999-7] 1 2 R. J. Buta; M. L. McCall (1999). "The IC 342/Maffei Group Revealed". Astrophysical Journal Supplement Series. 124 (1): 33–93. Bibcode:1999ApJS..124...33B. doi: 10.1086/313255 .

[maffei1968-8] P. Maffei (1968). "Infrared Object in the Region of IC 1895". Publications of the Astronomical Society of the Pacific. 80 (476): 618–621. Bibcode:1968PASP...80..618M. doi: 10.1086/128698 .

[karachentsevetal2003-9] I. D. Karachentsev; M. E. Sharina; A. E. Dolphin; E. K. Grebel (2003). "Distances to nearby galaxies around IC 342". Astronomy and Astrophysics. 408 (1): 111–118. Bibcode:2003A&A...408..111K. doi: 10.1051/0004-6361:20030912 .

[valtonenetal1993-10] M. J. Valtonen; G. G. Byrd; M. L. McCall; K. A. Innanen (1993). "A revised history of the Local Group and a generalized method of timing". Astronomical Journal. 105: 886–893. Bibcode:1993AJ....105..886V. doi:10.1086/116480.

[fingerhutetal2006-11] 1 2 R. L. Fingerhut; H. Lee; M. L. McCall; M. G. Richer (2007). "The Extinction and Distance of Maffei 2 and a New View of the IC 342/Maffei Group". Astrophysical Journal. 655 (2): 814–830. arXiv: astro-ph/0610044 . Bibcode:2007ApJ...655..814F. doi:10.1086/509862. S2CID 18405597.

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