NGC 681 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Cetus |
Right ascension | 01h 49m 10.829s [1] |
Declination | −10° 25′ 35.13″ [1] |
Redshift | 0.00587 ± 0.00002 [1] |
Heliocentric radial velocity | 1760.4 ± 6.6 km/s [1] |
Distance | ~66.5 million ly (20.39 ± 1.45 Mpc) [1] |
Group or cluster | MCG -02-05-053 Group (LGG 33) |
Apparent magnitude (V) | 12 [2] |
Characteristics | |
Type | SAB(s)ab |
Mass | 1.9×1010 [3] M☉ |
Mass/Light ratio | 3.6 [3] M☉/L☉ |
Size | ~29.07 kpc (diameter) [1] |
Apparent size (V) | 2.70 × 1.8 arcmin [2] [4] |
Other designations | |
IRAS 01467-1040, MCG -02-05-052, PGC 6671 [5] |
NGC 681 is an intermediate spiral galaxy in the constellation of Cetus, located approximately 66.5 million light-years from Earth. [1] [2] [4]
NGC 681 is a member of the MCG -02-05-053 group (also known as LGG 33), which contains four galaxies, including NGC 701 and IC 1738. [6]
NGC 681 was discovered by the German-born British astronomer William Herschel on 28 November 1785 and was later also observed by William's son, John Herschel. [2] John Louis Emil Dreyer, compiler of the first New General Catalogue of Nebulae and Clusters of Stars, described NGC 681 as being a "pretty faint, considerably large, round, small (faint) star 90 arcsec to [the] west" that becomes "gradually a little brighter [in the] middle". [2]
NGC 681 shares many structural similarities with the Sombrero Galaxy, M104, although it is smaller, less luminous, and less massive. Its thin, dusty disc is seen almost perfectly edge-on and features a small, very bright nucleus in the center of a very pronounced bulge. [7] Distinctly unlike M104, NGC 681's disc contains many H II regions, where star formation is likely to be occurring. [3] [7] The galaxy has a mass of 1.9×1010 M☉, a mass-to-light ratio of 3.6 , and a spiral pattern which is asymmetrical. [3]
The SIMBAD database lists NGC 681 as a Seyfert II Galaxy, i.e. it has a quasar-like nucleus with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable. [8]
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.
The Black Eye Galaxy is a relatively isolated spiral galaxy 17 million light-years away in the mildly northern constellation of Coma Berenices. It was discovered by Edward Pigott in March 1779, and independently by Johann Elert Bode in April of the same year, as well as by Charles Messier the next year. A dark band of absorbing dust partially in front of its bright nucleus gave rise to its nicknames of the "Black Eye", "Evil Eye", or "Sleeping Beauty" galaxy. M64 is well known among amateur astronomers due to its form in small telescopes and visibility across inhabited latitudes.
The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs, making it slightly bigger in size than the Milky Way.
NGC 5866 is a lenticular galaxy in the constellation Draco. NGC 5866 was most likely discovered by Pierre Méchain or Charles Messier in 1781, and independently found by William Herschel in 1788. Measured orbital velocities of its globular cluster system imply that dark matter makes up only 34%±45% of the mass within 5 effective radii, a notable paucity.
NGC 3079 is a barred spiral galaxy about 50 million light-years away, and located in the constellation Ursa Major. The galaxy was discovered by German-British astronomer William Herschel on 1 April 1790.
NGC 514 is a low-luminosity, intermediate spiral galaxy in the equatorial constellation of Pisces, located at a distance of approximately 83 million light-years from the Milky Way. It was discovered on 16 October 1784 by astronomer William Herschel. The general form of the galaxy is specified by its morphological classification of SAB(rs)c, which indicates it has a weak bar system at the core (SAB), an incomplete ring formation around the bar (rs), and somewhat loosely-wound spiral arms (c). This galaxy has an H II nucleus with an extended region that displays weak emission lines in the optical range, but not in the near infrared. The suspected supermassive black hole at the core has an estimated mass of 3.2×106 M☉.
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 4261 is an elliptical galaxy located around 100 million light-years away in the constellation Virgo. It was discovered April 13, 1784, by the German-born astronomer William Herschel. The galaxy is a member of its own somewhat meager galaxy group known as the NGC 4261 group, which is part of the Virgo Cluster.
NGC 4639 is a barred spiral galaxy located in the equatorial constellation of Virgo. It was discovered by German-born astronomer William Herschel on April 12, 1784. John L. E. Dreyer described it as "pretty bright, small, extended, mottled but not resolved, 12th magnitude star 1 arcmin to southeast". This is a relatively nearby galaxy, lying approximately 72 million light-years away from the Milky Way. It is a companion to NGC 4654, and the two appear to have interacted roughly 500 million years ago. NGC 4639 is a member of the Virgo Cluster.
NGC 2775, also known as Caldwell 48, is a spiral galaxy in the constellation Cancer. It is 67 million light-years away from the Milky Way. It was discovered by William Herschel in 1783. NGC 2775 belongs to the Antlia-Hydra Cluster of galaxies and is the most prominent member of the NGC 2775 Group, a small galaxy group in the Virgo Super-cluster, along with the Local Group. Other members of the NGC 2775 Group include NGC 2777 and UGC 4781.
NGC 6217 is a barred spiral galaxy located some 67 million light years away, in the constellation Ursa Minor. It can be located with a 10 cm (4 in) or larger telescope as an 11th magnitude object about 2.5° east-northeast of the star Zeta Ursae Minoris. The galaxy is inclined by an angle of 33° to the line of sight along a position angle of 162°.
NGC 2613 is a spiral galaxy in the southern constellation of Pyxis, next to the western constellation border with Puppis. It was discovered by the German-born astronomer William Herschel on November 20, 1784. With an apparent visual magnitude of 10.5, the galaxy is faintly visible using a telescope with a 100 mm (4 in) aperture. It appears spindle-shaped as it is almost edge-on to observers on Earth.
NGC 777 is an elliptical galaxy in the constellation of Triangulum. It was discovered by William Herschel on September 12, 1784. It has a weak active nucleus of type Seyfert 2 or LINER 2, implying that the central region is obscured. It may be an outlying member of galaxy cluster Abell 262.
NGC 1003 is a spiral galaxy at the western edge of the Perseus constellation. It is located at a distance of about 36 million light years from the Milky Way and is receding with a heliocentric radial velocity of 624 km/s. This galaxy was discovered by the Anglo-German astronomer William Herschel on October 6, 1784, who described it as "pretty faint, large, extended 90°±, much brighter middle, mottled but not resolved". It is a member of the NGC 1023 group of galaxies.
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 5395 is an interacting spiral galaxy located at a distance of 160 million light years, but receding away from the Earth at 3511 kilometers per second, in the constellation Canes Venatici. It was discovered by William Herschel on May 16, 1787. NGC 5395 and NGC 5394 are included in the Atlas of Peculiar Galaxies as Arp 84 in the category "Spiral galaxies with large high surface brightness companions".
NGC 4800 is an isolated spiral galaxy in the constellation Canes Venatici, located at a distance of 95 megalight-years from the Milky Way. It was discovered by William Herschel on April 1, 1788. The morphological classification of this galaxy is SA(rs)b, indicating a spiral galaxy with no visual bar at the nucleus (SA), an incomplete ring structure (rs), and moderately-tightly wound spiral arms (b). The galactic plane is inclined to the line of sight by an angle of 43°, and the long axis is oriented along a position angle of 25°. There is a weak bar structure at the nucleus that is visible in the infrared.
NGC 824 is a barred spiral galaxy located in the constellation Fornax about 260 million light-years from the Milky Way. It was discovered by British astronomer John Herschel in 1837.
NGC 676 is a lenticular Seyfert 2 galaxy in the constellation Pisces. Its velocity with respect to the cosmic microwave background is 1217 ± 20 km/s, which corresponds to a Hubble distance of 58.6 ± 4.2 Mly (17.96 ± 1.29 Mpc). In addition, two non redshift measurements give a distance of 61.0 ± 2.6 Mly (18.7 ± 0.8 Mpc). The galaxy was discovered by German-British astronomer William Herschel on 30 September 1786.
NGC 4868 is an unbarred spiral galaxy located about 240 million light-years away in the constellation Canes Venatici. It was discovered by William Herschel on March 17, 1787. A 2002 study suggests that a quasar may exist within NGC 4868.