Coma I

The Coma I Group is a group of galaxies[3][1] located about 14.5 Mpc (47.3 Mly)[7] away in the constellation Coma Berenices. The brightest member of the group is NGC 4725. The Coma I Group is rich in spiral galaxies while containing few elliptical and lenticular galaxies. Coma I lies in the foreground of the more distant Coma and Leo clusters and is located within the Virgo Supercluster.[3]

Coma I Group
NGC 4414, a flocculent spiral galaxy in the Coma I Group
Observation data (Epoch J2000)
Constellation(s)	Coma Berenices & Ursa Major
Right ascension	12^h 22^m 19.4^s[1][2]
Declination	29° 53′ 47″[1][2]
Brightest member	NGC 4725[3]
Number of galaxies	22–34[3][4][2][5][6]
Velocity dispersion	307 km/s[7]
Redshift	0.002418 (724 km/s)[1]
Distance (co-moving)	14.52 Mpc (47.4 Mly)[7]
Binding mass	2.5×10^12 [3] M☉
X-ray luminosity	1.6×10^43 erg/s [8]
Other designations
Coma I Group,[9] NGC 4274 Group,[1] LGG 279, LGG 294,[4] NBGG 14-01,[1][5] NBGG 14-02, NBGG 14 -2 +1,[9][5] NOGG H 611, NOGG P1 631, NOGG P2 642, NOGG P2 641[2]

The Coma I Group is currently infalling into the Virgo Cluster and will eventually merge with it.[10]

Structure

The Coma I Group appears to consist of two main subgroups, a denser subgroup centered on NGC 4274[11] and NGC 4278, and looser one surrounding NGC 4565 as suggested by De Vaucouleurs.[12] However, Gregory and Thompson (1977) found no clear evidence for two distinct subgroups in Coma I. They noted a slight density enhancement around NGC 4274 with the rest of the members of Coma I uniformly distributed to the southeast of this density enhancement. They also noted a central barlike structure with a minor axis of 0.9 Mpc (2.9 Mly) and a major axis of 2.3 Mpc (7.5 Mly).[3] P. Fouque et al. and A. M. Garcia et al. both list the Coma I group consisting of two subgroups centered on NGC 4274 and NGC 4565.[6][4] Additionally, Gibson et al. suggests that another association, the Coma II Group centered on NGC 4725 is associated with the Coma I Group.[9]

Members

The table below lists galaxies that have been commonly and consistently identified as group members in the Nearby Galaxies Catalog,[5] the survey of Fouque et al.,[6] the Lyons Groups of Galaxies (LGG) Catalog,[4] and the three group lists created from the Nearby Optical Galaxy sample of Giuricin et al.[2]

Members of the Coma I Group

Name	Type[13]	R.A. (J2000)[13]	Dec. (J2000)[13]	Redshift (km/s)[13]	Apparent Magnitude[13]
NGC 4020	SBd?	11^h 58^m 56.7^s	+30° 24′ 43″	760	13.1
NGC 4062	SA(s)c	12^h 04^m 03.8^s	+31° 53′ 45″	758	12.5
NGC 4136	SAB(r)c	12^h 09^m 17.7^s	+29° 55′ 39″	609	11.69
NGC 4173	SBd	12^h 12^m 21.4^s	+29° 12′ 25″	1127	13.59
NGC 4203	SAB0^-?	12^h 15^m 05.0^s	+33° 11′ 50″	1086	11.8
NGC 4245	SB0/a?(r)	12^h 17^m 36.8^s	+29° 36′ 29″	884	12.31
NGC 4251	SB0?	12^h 18^m 08.2^s	+28° 10′ 31″	1066	11.58
NGC 4274	(R)SB(r)ab	12^h 19^m 50.6^s	+29° 36′ 52″	930	11.34
NGC 4278	E1-2	12^h 20^m 06.8^s	+29° 16′ 51″	620	11.20
NGC 4283	E0	12^h 20^m 20.8^s	+29° 18′ 39″	1056	13.10
NGC 4310 (NGC 4338)	(R')SAB0^+(r)?	12^h 22^m 26.3^s	+29° 12′ 33″	913	13.22
NGC 4314	SB(rs)a	12^h 22^m 31.8^s	+29° 53′ 45″	963	11.43
NGC 4359	SB(rs)c?	12^h 24^m 11.2^s	+31° 31′ 19″	1253	13.6
NGC 4393	SABd	12^h 25^m 51.2^s	+27° 33′ 42″	755	12.7
NGC 4414	SA(rs)c?	12^h 26^m 27.1^s	+31° 13′ 25″	716	10.96
NGC 4448	SB(r)ab	12^h 28^m 15.4^s	+28° 37′ 13″	661	12.00
NGC 4494	E1-2	12^h 31^m 24.1^s	+25° 46′ 31″	1342	10.71
NGC 4525	Scd?	12^h 33^m 51.1^s	+30° 16′ 39″	1172	13.4
NGC 4559	SAB(rs)cd	12^h 35^m 57.6^s	+27° 57′ 36″	807	10.46
NGC 4562	SB(s)dm?	12^h 35^m 34.8^s	+25° 51′ 00″	1353	13.9
NGC 4565	SA(s)b?	12^h 36^m 20.8^s	+25° 59′ 16″	1230	10.42
NGC 4725	SAB(r)ab pec	12^h 50^m 26.6^s	+25° 30′ 03″	1206	10.11
NGC 4747	SBcd? pec	12^h 51^m 45.9^s	+25° 46′ 37″	1190	12.96

Other possible member galaxies (galaxies listed in only one or two of the lists from the above references) include IC 3215, IC 3247, MCG 5-29- 66, NGC 4080, NGC 4150, NGC 4308, NGC 4455, NGC 4509, NGC 4534, NGC 4627, NGC 4631, NGC 4656, NGC 4670, UGC 6900, UGC 7007, UGC 7300, UGC 7428, UGC 7438, UGC 7673, UGC 7916 and UGCA 294.

Nearby groups

The center of the Virgo Cluster (M87) lies about 3.6 Mpc (11.7 Mly) from the Coma I Group.[3]

See also

• List of Galaxy Groups
• M94 Group
• M96 Group
• Ursa Major Cluster – Another nearby spiral-rich group within the Virgo Supercluster

References

1. "Coma I Group". Retrieved 2018-05-12.
2. G. Giuricin; C. Marinoni; L. Ceriani; A. Pisani (2000). "Nearby Optical Galaxies: Selection of the Sample and Identification of Groups". Astrophysical Journal. 543 (1): 178–194. arXiv:astro-ph/0001140. Bibcode:2000ApJ...543..178G. doi:10.1086/317070.
3. Gregory, Stephen A.; Thompson, Laird A. (April 1977). "The Coma i Galaxy Cloud". The Astrophysical Journal. 213: 345–350. Bibcode:1977ApJ...213..345G. doi:10.1086/155160. ISSN 0004-637X.
4. A. Garcia (1993). "General study of group membership. II – Determination of nearby groups". Astronomy and Astrophysics Supplement. 100: 47–90. Bibcode:1993A&AS..100...47G.
5. R. B. Tully (1988). Nearby Galaxies Catalog. Cambridge: Cambridge University Press. ISBN 0-521-35299-1.
6. P. Fouque; E. Gourgoulhon; P. Chamaraux; G. Paturel (1992). "Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members". Astronomy and Astrophysics Supplement. 93: 211–233. Bibcode:1992A&AS...93..211F.
7. Boselli, A.; Gavazzi, G. (2009-10-21). "The HI properties of galaxies in the Coma I cloud revisited". Astronomy & Astrophysics. 508 (1): 201–207. arXiv:0909.4140. Bibcode:2009A&A...508..201B. doi:10.1051/0004-6361/200912658. ISSN 0004-6361.
8. Garcia-Barreto, J. A.; Downes, D.; Huchtmeier, W. K. (August 1994). "H I deficiency in the Coma I cloud of galaxies" (PDF). Astronomy and Astrophysics. 288: 705–712. Bibcode:1994A&A...288..705G.
9. Gibson, Brad K.; Hughes, Shaun M. G.; Stetson, Peter B.; Freedman, Wendy L.; Robert C. Kennicutt, Jr.; Mould, Jeremy R.; Bresolin, Fabio; Ferrarese, Laura; Ford, Holland C. (1999). "The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. XVII. The Cepheid Distance to NGC 4725". The Astrophysical Journal. 512 (1): 48. arXiv:astro-ph/9810003. Bibcode:1999ApJ...512...48G. doi:10.1086/306762. ISSN 0004-637X.
10. Tully, R. B.; Shaya, E. J. (June 1984). "Infall of galaxies into the Virgo cluster and some cosmological constraints". The Astrophysical Journal. 281: 31–55. Bibcode:1984ApJ...281...31T. doi:10.1086/162073. ISSN 0004-637X.
11. "Nearby Groups of Galaxies". ned.ipac.caltech.edu. Retrieved 2018-05-19.
12. Forbes, Duncan A. (October 1996). "Globular Cluster Luminosity Functions and the Hubble Constant From WFPC Imaging: Galaxies in the Coma I Cloud". The Astronomical Journal. 112: 1409. arXiv:astro-ph/9611139. Bibcode:1996AJ....112.1409F. doi:10.1086/118108. ISSN 0004-6256.
13. "NASA/IPAC Extragalactic Database". Results for various galaxies. Retrieved 2006-10-15.