A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a thousand stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies.
Messier 63 or M63, also known as NGC 5055 or the seldom-used Sunflower Galaxy, is a spiral galaxy in the northern constellation of Canes Venatici with approximately 400 billion stars. M63 was first discovered by the French astronomer Pierre Méchain, then later verified by his colleague Charles Messier on June 14, 1779. The galaxy became listed as object 63 in the Messier Catalogue. In the mid-19th century, Anglo-Irish astronomer Lord Rosse identified spiral structures within the galaxy, making this one of the first galaxies in which such structure was identified.
Messier 95, also known as M95 or NGC 3351, is a barred spiral galaxy about 33 million light-years away in the zodiac constellation Leo. It was discovered by Pierre Méchain in 1781, and catalogued by compatriot Charles Messier four days later. In 2012 its most recent supernova was discovered.
NGC 6946, sometimes referred to as the Fireworks Galaxy, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 in the constellation Ursa Major. Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.
Eridanus is a constellation in the southern celestial hemisphere. It is represented as a river. One of the 48 constellations listed by the 2nd century astronomer Ptolemy, it remains one of the 88 modern constellations. It is the sixth largest of the modern constellations, and the one that extends farthest in the sky from north to south. The same name was later taken as a Latin name for the real Po River and also for the name of a minor river in Athens.
NGC 1512 is a barred spiral galaxy approximately 38 million light-years away from Earth in the constellation Horologium. The galaxy displays a double ring structure, with a (nuclear) ring around the galactic nucleus and an (inner) further out in the main disk. The galaxy hosts an extended UV disc with at least 200 clusters with recent star formation activity. NGC 1512 is a member of the Dorado Group.
NGC 1637 is an isolated, non-interacting intermediate spiral galaxy in the constellation Eridanus, about a degree to the WNW of the star Mu Eridani. It is located at a distance of about 9.77 ± 1.82 Mpc (31.9 ± 5.9 Mly) from the Milky Way. The galaxy is inclined at an angle of 31.1° to the line of sight from the Earth and the long axis is oriented along a position angle of 16.3°.
NGC 1232, also known as the Eye of God Galaxy is an intermediate spiral galaxy about 60 million light-years away in the constellation Eridanus. It was discovered by German-British astronomer William Herschel on 20 October 1784.
NGC 1309 is a spiral galaxy located approximately 120 million light-years away, appearing in the constellation Eridanus. It is about 75,000 light-years across, and is about 3/4s the width of the Milky Way. Its shape is classified as SA(s)bc, meaning that it has moderately wound spiral arms and no ring. Bright blue areas of star formation can be seen in the spiral arms, while the yellowish central nucleus contains older-population stars. NGC 1309 is one of over 200 members of the Eridanus Group of galaxies.
NGC 908 is an unbarred spiral galaxy in the constellation Cetus. It was discovered in 1786 by William Herschel. This galaxy is 56 million light years away from Earth. It is the main galaxy in the NGC 908 group, which also includes NGC 899, NGC 907, and IC 223.
NGC 7013 is a relatively nearby spiral or lenticular galaxy estimated to be around 37 to 41.4 million light-years away from Earth in the constellation of Cygnus. NGC 7013 was discovered by English astronomer William Herschel on July 17, 1784 and was also observed by his son, astronomer John Herschel on September 15, 1828.
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.
ESO 269-57 is a large barred spiral galaxy located about 150 million light-years away in the constellation Centaurus. ESO 269-57 has a diameter of about 200,000 light-years. It is part of group of galaxies known as LGG 342. which is also known as the NGC 5064 Group which is part of the Centaurus Supercluster.
NGC 1189 is a barred spiral galaxy approximately 105 million light-years away from Earth in the constellation of Eridanus. It was discovered by American astronomer Francis Leavenworth on December 2, 1885 with the 26" refractor at Leander McCormick Observatory.
NGC 3312 is a large and highly inclined spiral galaxy located about 194 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 26, 1835. It was later rediscovered by astronomer Guillaume Bigourdan on February 26, 1887. NGC 3312 was later listed and equated with IC 629 because the two objects share essentially the same celestial coordinates. NGC 3312 is the largest spiral galaxy in the Hydra Cluster and is also classified as a LINER galaxy.
NGC 3883 is a large low surface brightness spiral galaxy located about 330 million light-years away in the constellation Leo. NGC 3883 has a prominent bulge but does not host an AGN. The galaxy also has flocculent spiral arms in its disk. It was discovered by astronomer William Herschel on April 13, 1785 and is a member of the Leo Cluster.
NGC 3810 is a spiral galaxy located in the constellation Leo. It is about 50 million light years from Earth, and estimated to be about 60,000 light years in diameter. William Herschel discovered it on 15 March 1784.
NGC 2835 is an intermediate spiral galaxy located in the constellation Hydra. It is located at a distance of circa 35 million light years from Earth, which, given its apparent dimensions, means that NGC 2835 is about 65,000 light years across. It was discovered by Wilhelm Tempel on April 13, 1884. NGC 2835 is located only 18.5 degrees from the galactic plane.
NGC 7541 is a barred spiral galaxy located around 104 million light-years away in the constellation Pisces. It was discovered in 1785 by William Herschel, and it is 106,000 light-years across. NGC 7541 is known to have lots of star-forming regions.
NGC 1100 is a spiral galaxy located around 235 million light-years away in the constellation Eridanus. NGC 1100 is situated close to the celestial equator, and it was discovered on October 17, 1885, by Francis Preserved Leavenworth. NGC 1100 is not known to have much star formation, and is not known to have an active galactic nucleus.
