NGC 1808 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Columba [1] |
Right ascension | 05h 07m 42.331s [2] |
Declination | −37° 30′ 45.88″ [2] |
Redshift | 0.003339 [2] |
Distance | 41.7 ± 3.9 Mly (12.8 ± 1.2 Mpc) [3] |
Group or cluster | Dorado Group |
Apparent magnitude (V) | 9.94 [4] |
Apparent magnitude (B) | 10.83 [5] |
Characteristics | |
Type | (R)SAB(s)a [6] |
Size | ~88,100 ly (27.01 kpc) (estimated) [2] |
Apparent size (V) | 7′.41 × 3′.39 [7] |
Other designations | |
ESO 305- G 008, IRAS 05059-3734, MCG -06-12-005, PGC 16779 [2] |
NGC 1808 is a barred spiral galaxy [3] located in the southern constellation of Columba, about two degrees to the south and east of Gamma Caeli. [1] It was discovered on 10 May 1826 by Scottish astronomer James Dunlop, who described it as a "faint nebula". [8] [9] The galaxy is a member of the NGC 1808 group, which is part of the larger Dorado Group. [8]
The morphological classification of this galaxy is (R)SAB(s)a, [6] which indicates a spiral galaxy with a weak-bar around the nucleus (SAB), no ring around the bar (s), an outer ring (R), and tightly-wound spiral arms (a). It is inclined by an angle of 57° to the line of sight from the Earth, with the long axis oriented at a position angle of 324°. [3] The disk of gas and stars shows a noticeable warp, and there is a pronounced asymmetry in the distribution of neutral hydrogen and H II regions. [10]
The core region contains a suspected weak active galactic nucleus plus a circumnuclear ring containing star clusters and supernova remnants at a distance of ~280 pc from the center. These form a ring of peculiar "hot spots". [11] It was formerly identified as a possible Seyfert galaxy, [3] but evidence now points to starburst activity in a ~500 pc radius around the center. [12] A probable outflow of gas is directed to the north-east from the nucleus, forming prominent dust lanes. [3] The high level of star formation in this galaxy and the nearby NGC 1792 may indicate a recent, distant tidal interaction between the two. [10]
One supernova has been observed in NGC 1808: SN 1993af (type Ia, mag. 17) was discovered by Marina Wischnjewsky on 15 November 1993 at 220″ east and 94″ north of the galactic nucleus. [13] [14] [15]
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 14 June 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.
NGC 4725 is an intermediate barred spiral galaxy with a prominent ring structure, located in the northern constellation of Coma Berenices near the north galactic pole. It was discovered by German-born British astronomer William Herschel on April 6, 1785. The galaxy lies at a distance of approximately 40 megalight-years from the Milky Way. NGC 4725 is the brightest member of the Coma I Group of the Coma-Sculptor Cloud, although it is relatively isolated from the other members of this group. This galaxy is strongly disturbed and is interacting with neighboring spiral galaxy NGC 4747, with its spiral arms showing indications of warping. The pair have an angular separation of 24′, which corresponds to a projected linear separation of 370 kly. A tidal plume extends from NGC 4747 toward NGC 4725.
NGC 4194, the Medusa merger, is a galaxy merger in the constellation Ursa Major about 128 million light-years (39.1 Mpc) away. It was discovered on April 2, 1791 by German-British astronomer William Herschel. Due to its disturbed appearance, it is object 160 in Halton Arp's 1966 Atlas of Peculiar Galaxies.
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 5962 is a spiral galaxy in the equatorial constellation of Serpens Caput. It was discovered by the Anglo-German astronomer William Herschel on March 21, 1784. The NGC 5962 galaxy is located at a distance of 120 million light years and is receding with a heliocentric radial velocity of 1,957 km/s. It is the brightest member of the eponymously-named NGC 5962 group, which overlaps with the nearby NGC 5970 group; the two groups may be gravitationally bound.
NGC 6503 is a field dwarf spiral galaxy in the northern constellation of Draco. It was discovered by German astronomer Arthur von Auwers on July 22, 1854. The galaxy has an angular size of 7.1′ × 2.4′ and an apparent visual magnitude of 10.2. It is located at a distance of approximately 20.9 million light-years (6.40 Mpc) from the Milky Way galaxy. NGC 6503 may form the remote tip of a long chain of galaxies that extends out into the local void, forming a galaxy filament spanning 26 million light-years (8 Mpc).
NGC 2397 is a flocculent spiral galaxy located in the southern Volans constellation, about one degree to the SSE of Delta Volantis. English astronomer John Herschel discovered the galaxy on February 21, 1835. It is located at a distance of approximately 69 million light years from the Sun, and is a member of the small NGC 2442 group that includes NGC 2434.
NGC 4102 is an intermediate barred spiral galaxy located in the northern constellation of Ursa Major. It is visible in a small telescope and has an apparent visual magnitude of 11.2. The galaxy was discovered April 12, 1789 by William Herschel. J. L. E. Dreyer described it as "bright, pretty small, round, brighter middle and bright nucleus". This galaxy is located at a distance of 60 million light years and is receding with a heliocentric radial velocity of 837 km/s. It is a member of the Ursa Major group of galaxies.
NGC 4388 is an active spiral galaxy in the equatorial constellation of Virgo. It was discovered April 17, 1784 by Wilhelm Herschel. This galaxy is located at a distance of 57 million light years and is receding with a radial velocity of 2,524km/s. It is one of the brightest galaxies of the Virgo Cluster due to its luminous nucleus. NGC 4388 is located 1.3° to the west of the cluster center, which translates to a projected distance of ≈400 kpc.
NGC 4293 is a lenticular galaxy in the northern constellation of Coma Berenices. It was discovered by English astronomer William Herschel on March 14, 1784, who described it as "large, extended, resolvable, 6 or 7′ long". This galaxy is positioned to the north-northwest of the star 11 Comae Berenices and is a member of the Virgo Cluster of galaxies. It is assumed to lie at the same distance as the Virgo Cluster itself: around 54 million light years away. The galaxy spans an apparent area of 5.3 × 3.1 arc minutes.
NGC 672 is a spiral galaxy in the northern constellation of Triangulum, positioned around 2° to the southwest of the star Alpha Trianguli. The original object designated NGC 672 was discovered by the German-born astronomer William Herschel on 26 October 1786, but this was later cataloged as NGC 614. The object now identified as NGC 672 was discovered by John Herschel on 11 November 1827.
NGC 1792 is a spiral galaxy located in the southern Columba constellation. It was discovered by Scottish astronomer James Dunlop on October 4, 1826. This galaxy is located at a distance of about 36.4 million light-years and is receding from the Milky Way with a heliocentric radial velocity of 1,208 km/s. NGC 1792 is a member of the NGC 1808 cluster of galaxies.
NGC 3610 is an elliptical galaxy in the constellation Ursa Major. It was discovered on 8 April 1793 by German-British astronomer William Herschel. This galaxy is located at a distance of 106 million light-years (32.5 Mpc) from the Milky Way, and is receding with a galacto-centric radial velocity of 1,819 km/s.
NGC 3862 is an elliptical galaxy located 300 million light-years away in the constellation Leo. Discovered by astronomer William Herschel on April 27, 1785, NGC 3862 is an outlying member of the Leo Cluster.
NGC 4424 is a spiral galaxy located in the equatorial constellation of Virgo. It was discovered February 27, 1865 by German astronomer Heinrich Louis d'Arrest. This galaxy is located at a distance of 13.5 million light years and is receding with a heliocentric radial velocity of 442 km/s. It has a morphological class of SB(s)a, which normally indicates a spiral galaxy with a barred structure (SB), no inner ring feature (s), and tightly-wound spiral arms (a). The galactic plane is inclined at an angle of 62° to the line of sight from the Earth. It is a likely member of the Virgo Cluster of galaxies.
NGC 708 is an elliptical galaxy located 240 million light-years away in the constellation Andromeda and was discovered by astronomer William Herschel on September 21, 1786. It is classified as a cD galaxy and is the brightest member of Abell 262. NGC 708 is a weak FR I radio galaxy and is also classified as a type 2 Seyfert galaxy.
NGC 6951 is a barred spiral galaxy located in the constellation Cepheus. It is located at a distance of about 75 million light-years from Earth, which, given its apparent dimensions, means that NGC 6951 is about 100,000 light-years across. It was discovered by Jérôme Eugène Coggia in 1877 and independently by Lewis Swift in 1878.
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 5728 is an active barred spiral galaxy located 146 million light years away in the southern constellation of Libra. It was discovered on May 7, 1787 by William Herschel. The designation comes from the New General Catalogue of J. L. E. Dreyer, published in 1888. It has an apparent visual magnitude of 13.40 and spans an angle of 3.4 arcminutes. The galaxy shows a red shift of 0.00935 and has a heliocentric radial velocity of 2,803 km/s. It has an estimated mass of 72 billion times the mass of the Sun and stretches around 30 kpc across.
NGC 4123 is a modest-sized, strongly-barred spiral galaxy located 75 million light-years away in the equatorial constellation of Virgo. It was discovered February 25, 1784 by William Herschel. This is a member of the Virgo cluster, and it belongs to a group of three galaxies. A companion galaxy, NGC 4116, lies at an angular separation of 14′ to the southwest. There is no indication of an interaction between the two galaxies. The third member of the group is NGC 4179.