Seyfert galaxies are one of the two largest groups of active galaxies, along with quasar host galaxies. They have quasar-like nuclei with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.
Messier 77 (M77), also known as NGC 1068 or the Squid Galaxy, is a barred spiral galaxy in the constellation Cetus. It is about 47 million light-years (14 Mpc) away from Earth, and was discovered by Pierre Méchain in 1780, who originally described it as a nebula. Méchain then communicated his discovery to Charles Messier, who subsequently listed the object in his catalog. Both Messier and William Herschel described this galaxy as a star cluster. Today, however, the object is known to be a galaxy. It is one of the brightest Seyfert galaxies visible from Earth and has a D25 isophotal diameter of about 27.70 kiloparsecs (90,000 light-years).
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.
NGC 1532, also known as Haley's Coronet, is an edge-on barred spiral galaxy located approximately 50 million light-years from the Solar System in the constellation Eridanus. The galaxy was discovered by James Dunlop on 29 October 1826.
The Caldwell catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled by Patrick Moore as a complement to the Messier catalogue.
NGC 1566, sometimes known as the Spanish Dancer, is an intermediate spiral galaxy in the constellation Dorado, positioned about 3.5° to the south of the star Gamma Doradus. It was discovered on May 28, 1826 by Scottish astronomer James Dunlop. At 10th magnitude, it requires a telescope to view. The distance to this galaxy remains elusive, with measurements ranging from 6 Mpc up to 21 Mpc.
NGC 3432 is an edge-on spiral galaxy that can be found in the northern constellation of Leo Minor. It was discovered by German-British astronomer William Herschel on March 19, 1787. This galaxy is located at a distance of 40 million light-years (12.3 Mpc) from the Milky Way. It is interacting with UGC 5983, a nearby dwarf galaxy, and features tidal filaments and intense star formation. Because of these features, it was listed in Halton Arp's Atlas of Peculiar Galaxies.
NGC 54 is an edge-on spiral galaxy in the constellation of Cetus. The galaxy was discovered by Wilhelm Tempel in 1886, and he defined it as "very faint, pretty small, round." The galaxy is 90,000 light years in diameter, making it slightly smaller than the Milky Way.
NGC 4402 is a relatively near, edge-on spiral galaxy located around 50 million light-years from Earth. It is in the constellation of Virgo within the Virgo Cluster of galaxies. It can be seen when viewing Markarian's Chain.
NGC 128 is a lenticular galaxy in the constellation Pisces. It is approximately 190 million light-years from the Sun and has a diameter of about 165,000 light-years.
NGC 4762 is an edge-on lenticular galaxy in the constellation Virgo. It is at a distance of 60 million light years and is a member of the Virgo Cluster. The edge-on view of this particular galaxy, originally considered to be a barred spiral galaxy, makes it difficult to determine its true shape, but it is considered that the galaxy consists of four main components — a central bulge, a bar, a thick disc and an outer ring. The galaxy's disc is asymmetric and warped, which could be explained by NGC 4762 merging with a smaller galaxy in the past. The remains of this former companion may then have settled within NGC 4762's disc, redistributing the gas and stars and so changing the disc's morphology.
NGC 191 is a spiral galaxy located in the constellation Cetus. It was discovered on November 28, 1785, by William Herschel.
NGC 254 is a lenticular galaxy located in the constellation Sculptor. It was discovered by John Herschel in 1834. It is in a galaxy group with NGC 134.
NGC 266 is a massive barred spiral galaxy in the constellation Pisces. NGC 266 is located at a distance of 197 megalight-years from the Milky Way. It was discovered on September 12, 1784, by William Herschel. The form of this barred galaxy is described by its morphological classification of SB(rs)ab, which indicates a quasi-ring-like structure (rs) and moderate-to-tightly wound spiral arms (ab).
NGC 275 is a barred spiral galaxy located approximately 63 million light-years from the Solar System in the constellation Cetus. It is one of a pair of galaxies, the other being NGC 274. It was discovered on October 9, 1828, by John Herschel.
NGC 315 is an elliptical galaxy in the constellation Pisces. Its velocity with respect to the cosmic microwave background is 4635 ± 22 km/s, which corresponds to a Hubble distance of 223.0 ± 15.7 Mly (68.36 ± 4.80 Mpc). In addition, eight non-redshift measurements give a distance of 208.58 ± 22.28 Mly (63.950 ± 6.830 Mpc). It was discovered by German-British astronomer William Herschel on September 11, 1784.
NGC 326 is a dumbbell galaxy in the constellation Pisces. It was discovered on August 24, 1865 by Heinrich d'Arrest. It was described by Dreyer as "faint, a little extended, 9th or 10th magnitude star to southeast."
NGC 375 is an elliptical galaxy located in the constellation Pisces. It was discovered on September 12, 1784 by William Herschel. It was described by Dreyer as "pretty faint, small, round, brighter middle." Along with galaxies NGC 379, NGC 380, NGC 382, NGC 383, NGC 384, NGC 385, NGC 386, NGC 387 and NGC 388, NGC 375 forms a galaxy cluster called Arp 331.
NGC 4522 is an edge-on spiral galaxy located about 60 million light-years away within the Virgo Cluster in the constellation Virgo. NGC 4522 is losing its molecular gas though ram-pressure stripping as it plows though the cluster at a speed of more than 10 million kilometres per hour. The galaxy was discovered by astronomer John Herschel on January 18, 1828.
NGC 1325 is a flocculent spiral galaxy situated in the constellation of Eridanus. Located about 75 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 19 December 1799.
