NGC 7184 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Aquarius |
Right ascension | 22h 02m 39.8s [1] |
Declination | −20° 48′ 46″ [1] |
Redshift | 0.008739 +/- 0.000010 [1] |
Heliocentric radial velocity | 2620 ± 3 km/s [1] |
Distance | 99.3 ± 22.5 Mly (30.5 ± 6.9 Mpc) [1] |
Apparent magnitude (V) | 11.1 |
Characteristics | |
Type | SB(r)c [1] |
Apparent size (V) | 6.0′ × 1.5′ [1] |
Other designations | |
UGCA 425, ESO 601- G009, MCG -04-52-009, PGC 67904 [1] |
NGC 7184 is a barred spiral galaxy located in the constellation Aquarius. It is located at a distance of circa 100 million light years from Earth, which, given its apparent dimensions, means that NGC 7184 is about 175,000 light years across. It was discovered by William Herschel on October 28, 1783. [2]
NGC 7184 has a small, bright nucleus and an elliptical bulge, whose major axis is aligned with the major axis of the disk. There is a bar along the minor axis of the bulge, but the high inclination of the galaxy makes its presence uncertain. From the bar emanate two tightly wound symmetrical spiral arms that form a bright inner ring. [3] The diameter of the ring along its major axis is 1.71 arcminutes. [4] The arms feature HII regions, and as they emerge from the ring are flocculent, based on the HII distribution, while they begin to split again at the outermost part of the galaxy. [5] Dust lanes are observed in the inner part of the disk. [6]
An outlying HII region has been discovered near NGC 7184. It is located on the major axis of the optical disk, on the northeasterly receding edge. Its size is estimated to be 270 pc at the distance of the galaxy and its Hα luminosity, 1037.6 erg s−1. It could be an isolated extension of a spiral arm. [7]
One supernova has been observed in NGC 7184, SN 1984N. It was discovered visually by Robert Evans at magnitude 14, 60" east and 65" north of the nucleus on July 20, 1984. Its discovery was confirmed by T. Cragg at the Anglo-Australian Observatory. [8] Initially it was thought to be a variable star in our galaxy, [9] but later study of the object revealed it was indeed a supernova. [10] [11] It was identified as type I. [12]
NGC 7184 is the foremost galaxy of a small galaxy group known as the NGC 7184 group, which also includes NGC 7183. [13] A satellite galaxy lies 3 arcminutes to the south, at a projected separation of 28 kpc. [14]
The Pinwheel Galaxy is a face-on, unbarred, and counterclockwise spiral galaxy located 21 million light-years from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries.
Messier 83 or M83, also known as the Southern Pinwheel Galaxy and NGC 5236, is a barred spiral galaxy approximately 15 million light-years away in the constellation borders of Hydra and Centaurus. Nicolas-Louis de Lacaille discovered M83 on 17 February 1752 at the Cape of Good Hope. Charles Messier added it to his catalogue of nebulous objects in March 1781.
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.
Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major. It has a D25 isophotal diameter of 29.44 kiloparsecs (96,000 light-years). Because of its relative proximity to the Milky Way galaxy, large size, and active galactic nucleus (which harbors a 70 million M☉ supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for amateur astronomers. In late February 2022, astronomers reported that M81 may be the source of FRB 20200120E, a repeating fast radio burst.
Messier 74 is a large spiral galaxy in the equatorial constellation Pisces. It is about 32 million light-years away from Earth. The galaxy contains two clearly defined spiral arms and is therefore used as an archetypal example of a grand design spiral galaxy. The galaxy's low surface brightness makes it the most difficult Messier object for amateur astronomers to observe. Its relatively large angular size and the galaxy's face-on orientation make it an ideal object for professional astronomers who want to study spiral arm structure and spiral density waves. It is estimated that M74 hosts about 100 billion stars.
NGC 2841 is an unbarred spiral galaxy in the northern circumpolar constellation of Ursa Major. It was discovered on 9 March, 1788 by German-born astronomer William Herschel. J. L. E. Dreyer, the author of the New General Catalogue, described it as, "very bright, large, very much extended 151°, very suddenly much brighter middle equal to 10th magnitude star". Initially thought to be about 30 million light-years distant, a 2001 Hubble Space Telescope survey of the galaxy's Cepheid variables determined its distance to be approximately 14.1 megaparsecs or 46 million light-years. The optical size of the galaxy is 8.1′ × 3.5′.
NGC 4526 is a lenticular galaxy with an embedded dusty disc, located approximately 55 million light-years from the Solar System in the Virgo constellation and discovered on 13 April 1784 by William Herschel. Herschel observed it again on 28 December 1785, resulting in the galaxy being entered twice into the New General Catalogue.
NGC 4536 is an intermediate spiral galaxy in the constellation Virgo. It was discovered by German-British astronomer William Herschel on 24 January 1784.
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 178 is a Magellanic spiral galaxy in the constellation of Cetus. The compiler of the New General Catalogue, John Louis Emil Dreyer noted that NGC 178 was "faint, small, much extended 0°, brighter middle". It was discovered on November 3, 1885, by Ormond Stone.
NGC 4178 is the New General Catalogue identifier for a barred spiral galaxy in the equatorial constellation of Virgo. It was discovered April 11, 1825 by English astronomer John Herschel. Located some 43.8 million light years away, this galaxy spans 2.3 × 0.4 arc minutes and is seen at a low angle, being inclined by 77° to the line of sight from the Earth. The morphological classification of NGC 4178 is SB(rs)dm, indicating that it has a bar feature at the core, and, per the '(rs)', has traces of a ring-like structure surrounding the bar. The 'dm' suffix indicates the spiral arms are diffuse, broken, and irregular in appearance with no bulge at the nucleus. This galaxy is a member of the Virgo Cluster, which is the richest nearby group of galaxies outside the Local Group and forms the core of the Virgo Supercluster.
NGC 1084 is an unbarred spiral galaxy in the constellation Eridanus. It is located at a distance of about 63 million light-years away from the Milky Way. The galaxy was discovered by William Herschel on 10 January 1785. It has multiple spiral arms, which are not well defined. It belongs in the same galaxy group with NGC 988, NGC 991, NGC 1022, NGC 1035, NGC 1042, NGC 1047, NGC 1052 and NGC 1110. This group is in turn associated with the Messier 77 group.
NGC 4699 is an intermediate spiral galaxy located in the constellation Virgo. It is located at a distance of about 65 million light years from Earth, which, given its apparent dimensions, means that NGC 4699 is about 85,000 light years across. It was discovered by William Herschel in 1786. It is a member of the NGC 4699 Group of galaxies, which 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.
The Coma I Group is a group of galaxies located about 14.5 Mpc (47.3 Mly) away in the constellation Coma Berenices. The brightest member of the group is NGC 4725. The Coma I Group is rich in spiral galaxies while containing few elliptical and lenticular galaxies. Coma I lies in the foreground of the more distant Coma and Leo clusters and is located within the Virgo Supercluster.
NGC 2336 is a barred spiral galaxy located in the constellation Camelopardalis. It is located at a distance of circa 100 million light years from Earth, which, given its apparent dimensions, means that NGC 2336 is about 200,000 light years across. It was discovered by Wilhelm Tempel in 1876.
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 3367 is a barred spiral galaxy located in the constellation Leo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 3367 is about 85,000 light years across. It was discovered by William Herschel on March 19, 1784.
IC 5201 is a barred spiral galaxy located in the constellation Grus. It is located at a distance of about 35 million light years from Earth, which, given its apparent dimensions, means that IC 5201 is about 90,000 light years across. It was discovered by Joseph Lunt in 1900.
NGC 539 is a barred spiral galaxy in the constellation of Cetus south. It is estimated to be 429 million light years from the Milky Way and has a diameter of approximately 200,000 ly. It was discovered on 31 October 1885 by American astronomer Francis Leavenworth.