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	13h 24m [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	13h 29m 52.7s	+47° 11′ 43″	463 ± 3	9.0
M51B (NGC 5195)	SB0 pec	13h 29m 59.6s	+47° 15′ 58″	465 ± 10	10.5
NGC 5023	Scd	13h 12m 12.6s	+44° 02′ 28″	407 ± 1	12.9
NGC 5229	SB(s)d	13h 34m 02.8s	+47° 54′ 56″	364 ± 8	14.3
Sunflower Galaxy (M63)	SA(rs)bc	13h 15m 49.3s	+42° 01′ 45″	504 ± 4	9.3
UGC 8313	SB(s)c	13h 13m 53.9s	+42° 12′ 31″	593 ± 4	14.4
UGC 8331	IAm	13h 15m 30.3s	+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