The M51 Group is a group of galaxies located in Canes Venatici

Canes Venatici

Canes Venatici is one of the 88 official modern constellations. It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for "hunting dogs", and the constellation is often depicted in illustrations as representing the dogs of Boötes the...

. The group is named after the brightest galaxy in the group, the Whirlpool Galaxy

Whirlpool Galaxy

The Whirlpool Galaxy is an interacting grand-design spiral galaxy that is estimated to be 23 ± 4 million light-years from the Milky Way Galaxy. in the constellation Canes Venatici...

 (M51A). Other notable members include the companion galaxy to the Whirlpool Galaxy (M51B

NGC 5195

NGC 5195 is a dwarf galaxy that is interacting with the Whirlpool Galaxy . Both galaxies are located approximately 25 million light-years away in the constellation Canes Venatici...

) and the Sunflower Galaxy

Sunflower Galaxy

The Sunflower Galaxy is a spiral galaxy in the constellation Canes Venatici consisting of a central disc surrounded by many short spiral arm segments...

 (M63).

Members

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

Members of the M51 Group

Name	Type	R.A. Right ascension Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...  (J2000)	Dec. Declination In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...  (J2000)	Redshift Redshift In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...  (km/s Second The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock.... )	Apparent Magnitude Apparent magnitude The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
M51B (NGC 5195) NGC 5195 NGC 5195 is a dwarf galaxy that is interacting with the Whirlpool Galaxy . Both galaxies are located approximately 25 million light-years away in the constellation Canes Venatici...	SB0 pec			465 ± 10	10.5
NGC 5023 NGC 5023 NGC 5023 is an edge-on spiral galaxy located in the constellation Canes Venatici. It is considered a member of the M51 Group although it is actually relatively isolated from other galaxies. It is approximately 15 kiloparsecs across and contains more than 200 stars with an apparent magnitude of...	Scd			407 ± 1	12.9
NGC 5229 NGC 5229 NGC 5229 is an edge-on spiral galaxy located in the constellation Canes Venatici. It is a member of the M51 Group although in reality it is relatively isolated from other galaxies. The galaxy's disc is somewhat warped and appears to consist of a series of interconnected clusters of stars from our...	SB(s)d			364 ± 8	14.3
Sunflower Galaxy (M63) Sunflower Galaxy The Sunflower Galaxy is a spiral galaxy in the constellation Canes Venatici consisting of a central disc surrounded by many short spiral arm segments...	SA(rs)bc			504 ± 4	9.3
UGC 8313 UGC 8313 UGC 8313 is an edge-on spiral galaxy located in the constellation Canes Venatici. It is a member of the M51 Group of galaxies and measures about 6 kiloparsecs in diameter and has a mass of about 1M☉...	SB(s)c			593 ± 4	14.4
UGC 8331 UGC 8331 UGC 8331 is an irregular galaxy located in the constellation Canes Venatici. It is a member of the M51 Group of galaxies and measures approximately 5 x 1.5 kiloparsecs . The galaxy's large-scale structure is very unorganized and it has two clusters of stars in its outer portions in addition to the...	IAm			260 ± 5	14.6
Whirlpool Galaxy (M51A) Whirlpool Galaxy The Whirlpool Galaxy is an interacting grand-design spiral galaxy that is estimated to be 23 ± 4 million light-years from the Milky Way Galaxy. in the constellation Canes Venatici...	SA(s)bc pec			463 ± 3	9.0

Other probable members (galaxies listed in two or more of the lists from the above references) include IC 4263 and UGC 8320

UGC 8320

UGC 8320 is a dwarf irregular galaxy located in the constellation Canes Venatici. The galaxy measures approximately 4 × 1.5 kiloparsecs and has a large number of H II regions scattered across most of the observable face...

. The exact membership is somewhat uncertain.

Nearby Groups

The M51 Group is located to the southeast of the M101 Group

M101 Group

The M101 Group is a loose group of galaxies located in Ursa Major. The group is named after the brightest galaxy in the group, the Pinwheel Galaxy . Most of the other members of the group are companions of the Pinwheel Galaxy. The group itself is one of many located within the Virgo Supercluster...

 and the NGC 5866 Group

NGC 5866 Group

The NGC 5866 Group is a small group of galaxies located in the constellation Draco. The group is named after NGC 5866, the galaxy with the highest apparent magnitude in the group, although some galaxy group catalogs list NGC 5907 as the brightest member....

. 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. However, most group identification methods (including those used by the references cited above) identify these three groups as separate entities.