View source for IC 342/Maffei Group

{{Short description|Galaxy cluster in the constellation of Cassiopeia}}
{{redirect-distinguish|Maffei Group|Maffei (company)}}
{{Galaxy cluster
| name = IC 342/Maffei Group
| image = [[Image:Maf1atlas.jpg|275px]]
| caption = Maffei 1, one of the brightest galaxies in the group
| epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]]
| ra =
| dec =
| constellation = [[Cassiopeia (constellation)|Cassiopeia]]/[[Camelopardalis]]/[[Perseus (constellation)|Perseus]] 
| member_no = 16<ref name="karachentsev2005" />
| brightest_member = [[IC 342]]<ref name="karachentsev2005" />
| other_names = IC 342 Group, Maffei 1 Group, [[Lyons Groups of Galaxies|LGG]] 104
}}

The '''IC 342/Maffei Group''' (also known as the '''IC 342 Group''' or the '''Maffei 1 Group''') corresponds to one or two [[galaxy group]]s 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.<ref name="karachentsev2005">{{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
 }}</ref>  The group is part of the [[Virgo Supercluster]].<ref name="tully1982">{{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
  }}</ref> 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.<ref>{{cite journal|doi=10.1134/S1990341318030021|title=Does the IC 342/Maffei Galaxy Group Really Exist?|year=2018|last1=Tikhonov|first1=N. A.|last2=Galazutdinova|first2=O. A.|journal=Astrophysical Bulletin|volume=73|issue=3|pages=279–292|bibcode=2018AstBu..73..279T|s2cid=126018966}}</ref><ref>{{cite journal|doi=10.3847/2041-8213/aafee6|title=The Distance and Motion of the Maffei Group|year=2019|last1=Anand|first1=Gagandeep S.|last2=Tully|first2=R. Brent|last3=Rizzi|first3=Luca|last4=Karachentsev|first4=Igor D.|journal=The Astrophysical Journal|volume=872|issue=1|pages=L4|arxiv=1901.05981|bibcode=2019ApJ...872L...4A|s2cid=119227716 |doi-access=free }}</ref>

==Members==

The table below lists galaxies that have been identified as associated with the IC342/Maffei 1 Group by I. D. Karachentsev.<ref name="karachentsev2005" /><ref name=Karachentsev2020>{{cite journal|doi=10.1051/0004-6361/202037993|title=KKH 22, the first dwarf spheroidal satellite of IC 342|year=2020|last1=Karachentsev|first1=Igor D.|last2=Makarova|first2=Lidia N.|last3=Brent Tully|first3=R.|last4=Anand|first4=Gagandeep S.|last5=Rizzi|first5=Luca|last6=Shaya|first6=Edward J.|last7=Afanasiev|first7=Viktor L.|s2cid=218538458|journal=Astronomy & Astrophysics|volume=638|pages=A111|arxiv=2005.03132|bibcode=2020A&A...638A.111K}}</ref> Note that Karachentsev divides this group into two subgroups centered around [[IC 342]] and [[Maffei 1]].
 
{| class="wikitable" style="text-align:center;border-collapse:collapse;" cellpadding="2"
|+'''Members of the IC 342 Subgroup'''
|-
! style="background:#efefef;" | Name
! style="background:#efefef;" | [[Galaxy morphological classification|Type]]<ref name="ned">{{cite web
  | title=NASA/IPAC Extragalactic Database
  | work=Results for various galaxies
  | url=http://nedwww.ipac.caltech.edu/
  | access-date=2006-12-30}}</ref>
! style="background:#efefef;" | [[Right ascension|R.A.]] ([[Epoch (astronomy)#Julian years and J2000|J2000]])<ref name="ned" />
! style="background:#efefef;" | [[Declination|Dec.]] ([[Epoch (astronomy)#Julian years and J2000|J2000]])<ref name="ned" />
! style="background:#efefef;" | [[Redshift]] (km/[[second|s]])<ref name="ned" />
! style="background:#efefef;" | [[Apparent magnitude|Apparent Magnitude]]<ref name="ned" />
|- 
| [[Camelopardalis A]]
| Irr
| {{RA|04|26|16.3}}
| {{DEC|+72|48|21}}
| –46 ± 1
| 14.8
|- 
| [[Camelopardalis B]]
| Irr
| {{RA|04|53|07.1}}
| {{DEC|+67|05|57}}
| 77
| 16.1
|- 
| [[IC 342]]
| SAB(rs)cd
| {{RA|03|46|48.5}}
| {{DEC|+68|05|46}}
| 31 ± 3
| 9.1
|- 
| [[KK 35]]
| Irr
| {{RA|03|45|12.6}}
| {{DEC|+67|51|51}}
| 105 ± 1
| 17.2
|- 
| [[KKH 22]]<ref name=Karachentsev2020/>
| dSph
| {{RA|03|44|56.6}}
| {{DEC|+72|03|52}}
| 30 ±&nbsp;10
| 15.3
|- 
| [[NGC 1560]]
| SA(s)d
| {{RA|04|32|49.1}}
| {{DEC|+71|52|59}}
| –36 ± 5
| 12.2
|- 
| [[NGC 1569]]
| Sbrst	
| {{RA|04|30|49.1}}	
| {{DEC|+64|50|52,6}}
| –104 ± 4
| 11.2
|-
| [[UGCA 86]]
| Im
| {{RA|03|59|50.5}}
| {{DEC|+67|08|37}}
| 67 ± 4
| 13.5
|- 
| [[UGCA 92]]
| Im
| {{RA|04|32|04.9}}
| {{DEC|+63|36|49.0}}
| –99 ± 5
| 13.8
|-
| [[UGCA 105]]
| Im
| {{RA|05|14|15.3}}
| {{DEC|+62|34|48}}
| 111 ± 5
| 13.9
|-
|}

{| class="wikitable" style="text-align:center;border-collapse:collapse;" cellpadding="2"
|+'''Members of the Maffei 1 Subgroup'''
|-
! style="background:#efefef;" | Name
! style="background:#efefef;" | [[Galaxy morphological classification|Type]]<ref name="ned" />
! style="background:#efefef;" | [[Right ascension|R.A.]] ([[Epoch (astronomy)#Julian years and J2000|J2000]])<ref name="ned" />
! style="background:#efefef;" | [[Declination|Dec.]] ([[Epoch (astronomy)#Julian years and J2000|J2000]])<ref name="ned" />
! style="background:#efefef;" | [[Redshift]] (km/[[second|s]])<ref name="ned" />
! style="background:#efefef;" | [[Apparent magnitude|Apparent Magnitude]]<ref name="ned" />
|- 
| [[Dwingeloo 1]]
| SB(s)cd
| {{RA|02|56|51.9}}
| {{DEC|+58|54|42}}
| 110
| 8.3
|- 
| [[Dwingeloo 2]]
| Im
| {{RA|02|54|08.5}}
| {{DEC|+59|00|19}}
| 94 ± 1
| 20.5
|- 
| [[KKH 11]]
| dE
| {{RA|02|24|34.2}}
| {{DEC|+56|00|43}}
| 310
| 16.2
|- 
| [[KKH 12]]
| Irr
| {{RA|02|27|26.9}}
| {{DEC|+57|29|16}}
| 70
| 17.8
|- 
| [[Maffei 1]]
| S0 pec
| {{RA|02|36|35.4}}
| {{DEC|+59|39|19}}
| 13 ± 22
| 11.4
|- 
| [[Maffei 2]]
| SAB(rs)bc
| {{RA|02|41|55.1}}
| {{DEC|+59|36|15}}
| –17 ± 5
| 16.0
|- 
| [[MB 1]]
| SAB(s)d
| {{RA|02|35|36.5}}
| {{DEC|+59|22|43}}
| 190 ± 1
| 20.5
|- 
| [[MB 3]]
| dSph
| {{RA|02|55|42.7}}
| {{DEC|+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.<ref name="karachentsev2005" />

{{Wide image|Maffei 1 and 2.jpg|650px|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' [[luminosity|luminosities]] and distances as well as other related quantities.<ref name="karachentsev2005" /><ref name="butamccall1999">{{cite journal
  |author1=R. J. Buta |author2=M. L. McCall | title=The IC 342/Maffei Group Revealed
  | journal=Astrophysical Journal Supplement Series
  | date=1999
  | volume=124
  | issue= 1
  | pages=33–93
  | bibcode=1999ApJS..124...33B | doi = 10.1086/313255
| doi-access=free
  }}</ref>

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, [[Maffei 1]] and [[Maffei 2]] were only discovered in 1968 using [[infrared]] photographic images of the region.<ref name="maffei1968">{{cite journal
  | author= P. Maffei
  | title=Infrared Object in the Region of IC 1895
  | journal=Publications of the Astronomical Society of the Pacific
  | date=1968
  | volume=80
  | issue=476
  | pages=618–621
  | bibcode=1968PASP...80..618M | doi = 10.1086/128698
| doi-access=free
  }}</ref>  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]].<ref name="karachentsevetal2003">{{cite journal
  |author1=I. D. Karachentsev |author2=M. E. Sharina |author3=A. E. Dolphin |author4=E. K. Grebel | title=Distances to nearby galaxies around IC 342
  | journal=Astronomy and Astrophysics
  | date=2003
  | volume=408
  | issue= 1
  | pages=111–118
  | bibcode=2003A&A...408..111K | doi = 10.1051/0004-6361:20030912
| doi-access=free}}</ref>

==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.<ref name="valtonenetal1993">{{cite journal
  |author1=M. J. Valtonen |author2=G. G. Byrd |author3=M. L. McCall |author4=K. A. Innanen | title=A revised history of the Local Group and a generalized method of timing
  | journal=Astronomical Journal
  | date=1993
  | volume=105
  | pages=886–893
  | bibcode=1993AJ....105..886V | doi = 10.1086/116480
}}</ref>

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.<ref name="butamccall1999" /><ref name="fingerhutetal2006">{{cite journal
  |author1=R. L. Fingerhut |author2=H. Lee |author3=M. L. McCall |author4=M. G. Richer | title = The Extinction and Distance of Maffei 2 and a New View of the IC 342/Maffei Group
  | year = 2007
  | journal = Astrophysical Journal
  |volume=655 |issue=2 |pages=814–830 |arxiv=astro-ph/0610044
|bibcode = 2007ApJ...655..814F |doi = 10.1086/509862 |s2cid=18405597 }}</ref>  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.<ref name="fingerhutetal2006" />

==References==
{{Reflist}}

{{Commons category}}

{{DEFAULTSORT:IC 342 Maffei Group}}
[[Category:IC 342/Maffei Group| ]]
[[Category:Virgo Supercluster]]