M51 Group

The M51 Group is a group of galaxies located in Canes Venatici. The group is named after the brightest galaxy in the group, the Whirlpool Galaxy (M51A). Other notable members include the companion galaxy to the Whirlpool Galaxy (M51B) and the Sunflower Galaxy (M63).[1][2][4][3]

M51 Group
The Whirlpool Galaxy (M51A), the brightest member of the M51 Group, and M51B, the companion to the Whirlpool Galaxy.
Observation data (Epoch J2000)
Constellation(s)	Canes Venatici
Right ascension	13^h 24^m [1][2]
Declination	46° 13′[1][2]
Brightest member	Whirlpool Galaxy (M51A)[1][2][3]
Number of galaxies	7-17[1][2][4][3]
Other designations
NGC 5194 Group, LGG 347,[1] NOGG H 712,[2] NOGG P1 723,[2] NOGG P2 739[2]

Members

The table below lists galaxies that have been consistently identified as group members in the Nearby Galaxies Catalog,[4] the survey of Fouque et al.,[3] the Lyons Groups of Galaxies (LGG) Catalog,[1] and the three group lists created from the Nearby Optical Galaxy sample of Giuricin et al.[2]

Members of the M51 Group

Name	Type[5]	R.A. (J2000)[5]	Dec. (J2000)[5]	Redshift (km/s)[5]	Apparent Magnitude[5]
Whirlpool Galaxy (M51A)	SA(s)bc pec	13^h 29^m 52.7^s	+47° 11′ 43″	463 ± 3	9.0
M51B (NGC 5195)	SB0 pec	13^h 29^m 59.6^s	+47° 15′ 58″	465 ± 10	10.5
NGC 5023	Scd	13^h 12^m 12.6^s	+44° 02′ 28″	407 ± 1	12.9
NGC 5229	SB(s)d	13^h 34^m 02.8^s	+47° 54′ 56″	364 ± 8	14.3
Sunflower Galaxy (M63)	SA(rs)bc	13^h 15^m 49.3^s	+42° 01′ 45″	504 ± 4	9.3
UGC 8313	SB(s)c	13^h 13^m 53.9^s	+42° 12′ 31″	593 ± 4	14.4
UGC 8331	IAm	13^h 15^m 30.3^s	+47° 29′ 56″	260 ± 5	14.6

Other probable members (galaxies listed in two or more of the lists from the above references) include IC 4263 and UGC 8320. The exact membership is somewhat uncertain.

Nearby Groups

The M51 Group is located to the southeast of the M101 Group and the NGC 5866 Group.[6] The distances to these three groups (as determined from the distances to the individual member galaxies) are similar, which suggests that the M51 Group, the M101 Group, and the NGC 5866 Group are actually part of a large, loose, elongated structure.[6] However, most group identification methods (including those used by the references cited above) identify these three groups as separate entities.

See also

• Virgo Supercluster

References

1. 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.
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. P. Fouque, E. Gourgoulhon, P. Chamaraux, G. Paturel; Gourgoulhon; Chamaraux; 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.CS1 maint: multiple names: authors list (link)
4. R. B. Tully (1988). Nearby Galaxies Catalog. Cambridge: Cambridge University Press. ISBN 0-521-35299-1.
5. "NASA/IPAC Extragalactic Database". Results for various galaxies. Retrieved 2006-10-19.
6. L. Ferrarese, H. C. Ford, J. Huchra, R. C. Kennicutt Jr., J. R. Mould, S. Sakai, W. L. Freedman, P. B. Stetson, B. F. Madore, B. K. Gibson, J. A. Graham, S. M. Hughes, G. D. Illingworth, D. D. Kelson, L. Macri, K. Sebo, N. A. Silbermann (2000). "A Database of Cepheid Distance Moduli and Tip of the Red Giant Branch, Globular Cluster Luminosity Function, Planetary Nebula Luminosity Function, and Surface Brightness Fluctuation Data Useful for Distance Determinations". Astrophysical Journal Supplement. 128 (2): 431–459. arXiv:astro-ph/9910501. Bibcode:2000ApJS..128..431F. doi:10.1086/313391.CS1 maint: multiple names: authors list (link)

External links

• M51 group, SEDS Messier pages