A spiral galaxy is a type of galaxy characterized by a central bulge of old Population II stars surrounded by a rotating disc of younger Population I stars. A spiral galaxy maintains its spiral arms due to density wave theory.
Below is a list of notable spiral galaxies with their own articles. The classification column refers to the galaxy morphological classification used by astronomers to describe galaxy structure.
Aries is one of the constellations of the zodiac. It is located in the Northern celestial hemisphere between Pisces to the west and Taurus to the east. The name Aries is Latin for ram. Its old astronomical symbol is (♈︎). It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is a mid-sized constellation ranking 39th in overall size, with an area of 441 square degrees.
Messier 100 is a grand design intermediate spiral galaxy in the southern part of the mildly northern Coma Berenices. It is one of the brightest and largest galaxies in the Virgo Cluster and is approximately 55 million light-years from our galaxy, its diameter being 107,000 light years, and being about 60% as large. It was discovered by Pierre Méchain in 1781 and 29 days later seen again and entered by Charles Messier in his catalogue "of nebulae and star clusters". It was one of the first spiral galaxies to be discovered, and was listed as one of fourteen spiral nebulae by Lord William Parsons of Rosse in 1850. NGC 4323 and NGC 4328 are satellite galaxies of M100; the former is connected with it by a bridge of luminous matter.
Andromeda is one of the 48 constellations listed by the 2nd-century Greco-Roman astronomer Ptolemy, and one of the 88 modern constellations. Located in the northern celestial hemisphere, it is named for Andromeda, daughter of Cassiopeia, in the Greek myth, who was chained to a rock to be eaten by the sea monster Cetus. Andromeda is most prominent during autumn evenings in the Northern Hemisphere, along with several other constellations named for characters in the Perseus myth. Because of its northern declination, Andromeda is visible only north of 40° south latitude; for observers farther south, it lies below the horizon. It is one of the largest constellations, with an area of 722 square degrees. This is over 1,400 times the size of the full moon, 55% of the size of the largest constellation, Hydra, and over 10 times the size of the smallest constellation, Crux.
Perseus is a constellation in the northern sky, named after the Greek mythological hero Perseus. It is one of the 48 ancient constellations listed by the 2nd-century astronomer Ptolemy, and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located near several other constellations named after ancient Greek legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west. Some star atlases during the early 19th century also depicted Perseus holding the disembodied head of Medusa, whose asterism was named together as Perseus et Caput Medusae; however, this never came into popular usage.
Leo Minor is a small and faint constellation in the northern celestial hemisphere. Its name is Latin for "the smaller lion", in contrast to Leo, the larger lion. It lies between the larger and more recognizable Ursa Major to the north and Leo to the south. Leo Minor was not regarded as a separate constellation by classical astronomers; it was designated by Johannes Hevelius in 1687.
NGC 2207 and IC 2163 are a pair of colliding spiral galaxies about 80 million light-years away in the constellation Canis Major. Both galaxies were discovered by John Herschel in 1835.
NGC 27 is a spiral galaxy located in the constellation Andromeda. It was discovered on 3 August 1884 by Lewis Swift. It forms a galaxy pair with the nearby UGC 95.
Arp 272 is a pair of interacting galaxies consisting of the two spiral galaxies NGC 6050 (left) and IC 1179 (right). Arp 272 lies around 450 million light years from Earth in the constellation of Hercules. The galaxies are part of the Hercules Cluster, which is itself part of the CfA2 Great Wall.
NGC 78 is a pair of galaxies in the constellation Pisces. NGC 78A, which is the more southern galaxy, is a barred spiral galaxy. NGC 78B, which is the more northern galaxy, is an elliptical galaxy. Although the designations NGC 78A and 78B are used today, the designation NGC 78 was formerly used mainly for the northern galaxy.
NGC 334 is a barred spiral galaxy in the constellation Sculptor. It was discovered on September 25, 1834 by John Herschel. It was described by Dreyer as "very faint, small, round, gradually a little brighter middle, 2 stars of 11th magnitude to south."
NGC 5011 is an elliptical galaxy in the constellation of Centaurus. It was discovered on 3 June 1834 by John Herschel. It was described as "pretty bright, considerably small, round, among 4 stars" by John Louis Emil Dreyer, the compiler of the New General Catalogue.
NGC 5949 is a dwarf spiral galaxy located around 44 million light-years away in the constellation Draco. NGC 5949 was discovered in 1801 by William Herschel, and it is 30,000 light-years across. NGC 5949 is not known to have an Active galactic nucleus, and it is not known for much star-formation.
NGC 5559 is a barred spiral galaxy, located 240 million light-years away in the constellation of Boötes. It was discovered on April 10, 1785, by the astronomer William Herschel.
NGC 1345 is a barred spiral galaxy in the constellation Eridanus. It was discovered by John Herschel on Dec 11, 1835.
NGC 1374 is a low-luminosity elliptical galaxy in the southern constellation Fornax. It was discovered by John Herschel on November 29, 1837.
NGC 606 is a barred spiral galaxy located in the Pisces constellation about 470 million light-years from the Milky Way. It was discovered by the French astronomer Édouard Stephan in 1881.
NGC 1353 is a flocculent spiral galaxy situated in the constellation of Eridanus. Located about 70 million light years away, it is a member of the Eridanus cluster of galaxies, a cluster of about 200 galaxies. It was discovered by William Herschel on 9 December 1784.
NGC 600 is an emission-line galaxy in the constellation Cetus. It was discovered by William Herschel on 10 September 1785. The galaxy has a diameter of 70,000 light-years. It is also approximately 90 million light-years from the Milky Way.
NGC 5533 is an unbarred spiral galaxy in the constellation Boötes. It was discovered by the astronomer William Herschel on May 1, 1785. It has a regular structure, with one tightly wound spiral; its disk is inclined about 53 degrees towards the line of sight.
NGC 3602 is a barred spiral galaxy in the constellation Leo. It was discovered on March 4, 1865 by the astronomer Albert Marth.