{{Short description|Galaxy cluster in the constellations Coma Berenices and Canes Venatici}} {{Galaxy cluster | name = NGC 4631 Group | image = The Whale LRGB.jpg | caption = NGC 4631 and NGC 4627 top right. NGC 4656 and NGC 4657 bottom right. | epoch=J2000 | ra=12<sup>h</sup> 09<sup>m</sup><ref name="garcia1993">{{cite journal | author=A. M. Garcia | title=General study of group membership. II - Determination of nearby groups | journal=Astronomy and Astrophysics Supplement | date=1993 | volume=100 | pages=47–90 | bibcode=1993A&AS..100...47G}}</ref><ref name="giuricinetal2002">{{cite journal | author=G. Giuricin | author2=C. Marinoni | author3= L. Ceriani | author4= A. Pisani | title=Nearby Optical Galaxies: Selection of the Sample and Identification of Groups | journal=Astrophysical Journal | date=2000 | volume=543 | issue=1 | pages=178–194 | bibcode=2000ApJ...543..178G | doi=10.1086/317070|arxiv = astro-ph/0001140 | s2cid=9618325 }}</ref> | dec=+30° 02′<ref name="garcia1993"/><ref name="giuricinetal2002"/> | constellation = Canes Venatici<br/>& Coma Berenices | member_no = 5–27<ref name="garcia1993"/><ref name="giuricinetal2002"/><ref name="fouqueetal1992"/><ref name="nbg"/> | brightest_member = NGC 4631<ref name="giuricinetal2002"/><ref name="fouqueetal1992"/> | other_names = LGG 291,<ref name="garcia1993"/> NOGG H611,<ref name="giuricinetal2002"/><br/>NOGG P1 631,<ref name="giuricinetal2002"/> NOGG P2 642<ref name="giuricinetal2002"/>}}
The '''NGC 4631 Group''' is a poorly defined group of galaxies, about 25 million light-years from Earth in the Coma Berenices and Canes Venatici constellations.
The NGC 4631 Group is one of many that lie within the Virgo Supercluster.<ref name="fouqueetal1992"/>
==Members==
*spiral galaxy NGC 4631 (''Whale Galaxy''), brightest galaxy in the group <ref name="fouqueetal1992">{{cite journal | author=P. Fouque | author2=E. Gourgoulhon | author3=P. Chamaraux | author4=G. Paturel | title=Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members | journal=Astronomy and Astrophysics Supplement | date=1992 | volume=93 | pages=211–233 | bibcode=1992A&AS...93..211F}}</ref> *interacting galaxies NGC 4656 and NGC 4657 (''Hockey Stick Galaxies'') *dwarf elliptical galaxy NGC 4627, which is a companion of NGC 4631,<ref name="arp1966">{{cite journal | author=H. Arp | title=Atlas of Peculiar Galaxies | journal=Astrophysical Journal Supplement | date=1966 | volume=14 | pages=1–20 | bibcode=1966ApJS...14....1A | doi=10.1086/190147}}</ref> is also by default a member of the group, although it is not listed in most catalogs
Aside from these four galaxies, however, the determination of group membership is quite variable. The group lies in a relatively crowded part of the sky near the Virgo Cluster, so exact determination of the group membership is extremely difficult. Some studies have estimated that the NGC 4631 Group contains as few as five galaxies,<ref name="nbg">{{cite book | author=R. B. Tully | date=1988 | title=Nearby Galaxies Catalog | edition= | publisher=Cambridge University Press | location=Cambridge | isbn=0-521-35299-1}}</ref> while others place the estimate as high as 27.<ref name="giuricinetal2002"/> Additionally, it is unclear as to whether the galaxies near NGC 4631 and NGC 4656/NGC 4657 form one large group or two smaller groups.<ref name="garcia1993"/>
==See also== *Virgo Cluster
==References==
{{Reflist}}
==External links== *[http://antwrp.gsfc.nasa.gov/apod/ap090821.html The Whale and the Hockey Stick] Astronomy Picture of the Day of 2009 August 21
{{Canes Venatici}} {{Coma Berenices}}
{{DEFAULTSORT:NGC 4631 Group}} Category:NGC 4631 Group Category:Galaxy clusters Category:Coma Berenices Category:Canes Venatici Category:Virgo Supercluster