NGC 4593 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Virgo |
Right ascension | 12h 39m 39.4s [1] |
Declination | −05° 20′ 39″ [1] |
Redshift | 0.008312 ± 0.000020 [1] |
Heliocentric radial velocity | 2,492 ± 6 km/s [1] |
Distance | 120 ± 57 Mly (34.3 ± 16.8 Mpc) [1] |
Apparent magnitude (V) | 11.67 |
Characteristics | |
Type | (R)SB(rs)b [1] |
Apparent size (V) | 3.9′ × 2.9′ [1] |
Notable features | Seyfert galaxy |
Other designations | |
MRK 1330, MCG -01-32-032, PGC 42375 [1] |
NGC 4593 is a barred spiral galaxy located in the constellation Virgo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 4593 is about 125,000 light years across. [1] It was discovered by William Herschel on April 17, 1784. [2] It is a Seyfert galaxy. [1]
NGC 4593 is a barred spiral galaxy with a nearly complete ring. The galaxy has a large elliptical/boxy pseudobulge with the bar emerging from its northeast and southwest corner. From its end of the bar begin two diffuse smooth spiral arms that can be traced for about half a revolution. At the south part of the ring there could emerge a third, smaller spiral arm. [3] One arm emerges from the ring at one end of the bar while a second emerges about 15 degrees before the other end. [4]
The nucleus of NGC 4593 has been found to be active and it has been categorised as a type I Seyfert galaxy. [5] The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 4593 is estimated to be (9.8±2.1)×106 M☉ based on reverberation mapping [6] or (5.8±2.1)×106 M☉ based on X-ray flux variations. [7]
The nucleus has been found to be a bright X-rays source. The source is variable both in flux and spectrum, varying at a timescale of few kiloseconds. [8] The changes in the X-ray band are followed by variations in the ultraviolet and visual light band, with the lag being 1.3 ± 0.5 days in the V-band. [9] The X-rays observations by Chandra X-ray Observatory indicate the presence of a warm absorber and outflows of ionised gas that are generated at different distances from the nucleus. [10] The overall X-ray spectrum indicates the presence of a hot corona, which generates the hard X-rays, and a warm medium, which is responsible for the soft X-rays excess. [7]
A circumnuclear dust ring with a radius of 5 arcseconds that is connected with the dust lanes in the bar of the galaxy is seen in visible light. [4] Similar rings in other galaxies have been found to exhibit intense star formation, but that isn't the case with NGC 4593, indicating that starburst activity is episodic. [4] Inside the ring lies a single spiral arm and no other dust features. [11]
NGC 4593 is the foremost galaxy in a galaxy group known as NGC 4593 group. Other members of the group the spiral galaxy NGC 4602 and the smaller galaxies MCG-01-32-37, MGC-01-32-33, SVEN 314, and SVEN 328. [12] Markarov et al. consider NGC 4604 to be a member of this group as well. [13] SVEN 314 is a dwarf galaxy which lies at a projected distance of 22 kpc and is the closest galaxy to NGC 4593. [12] There are evidence that NGC 4693 is interracting with MGC-01-32-33, which lies about two disk radii away, as the spiral pattern is slightly distorted towards the direction of that galaxy, possibly as a result of tidal forces. [4]
Other galaxies near NGC 4593 group include UGC 7798 and its group, IC 804, NGC 4626, NGC 4628, and NGC 4671. [13] These galaxies were considered to be part of the Virgo II Groups, but that isn't accepted anymore, [12] and they are considered to lie between the Local Supercluster and Hydra-Centaurus Supercluster. [14]
Messier 94 is a spiral galaxy in the mid-northern constellation Canes Venatici. It was discovered by Pierre Méchain in 1781, and catalogued by Charles Messier two days later. Although some references describe M94 as a barred spiral galaxy, the "bar" structure appears to be more oval-shaped. The galaxy has two ring structures.
NGC 3227 is an intermediate spiral galaxy that is interacting with the dwarf elliptical galaxy NGC 3226. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies. Both galaxies may be found in the constellation Leo. It is a member of the NGC 3227 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.
NGC 5929 is a well-studied Seyfert galaxy in the constellation Boötes. It was discovered by English astronomer John Herschel on May 13, 1828. In the revised New General Catalogue it is described as "elongated, brighter toward the middle, with a slightly diffuse halo". This galaxy is located at an estimated distance of 133 million light-years. It forms an interacting pair with NGC 5930 at an angular separation of 0.5′; together they form entry number 90 in Halton Arp's 1966 Atlas of Peculiar Galaxies. A dust streak from NGC 5930 appears to lie in front of NGC 5929, suggesting that the former galaxy is the closer member of this pair.
NGC 5643 is an intermediate spiral galaxy in the constellation Lupus. Based on the tip of the red-giant branch distance indicator, it is located at a distance of about 40 million light-years. NGC 5643 has an active galactic nucleus and is a type II Seyfert galaxy.
NGC 7469 is an intermediate spiral galaxy in the constellation of Pegasus. NGC 7469 is located about 200 million light-years away from Earth, which means, given its apparent dimensions, that NGC 7469 is approximately 90,000 light-years across. It was discovered by William Herschel on November 12, 1784.
NGC 7213 is a lenticular galaxy located in the constellation Grus. It is located at a distance of circa 70 million light-years from Earth, which, given its apparent dimensions, means that NGC 7213 is about 75,000 light-years across. It was discovered by John Herschel on September 30, 1834. It is an active galaxy with characteristics between a type I Seyfert galaxy and LINER.
NGC 4939 is a spiral galaxy located in the constellation Virgo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 4939 is about 190,000 light years across. It was discovered by William Herschel on March 25, 1786.
NGC 7130 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 220 million light years from Earth, which, given its apparent dimensions, means that NGC 7130 is about 100,000 light years across. It was discovered by John Herschel on September 25, 1834, and discovered independently by Lewis Swift on September 17, 1897. The location of the galaxy given in the New General Catalogue was off by 30 arcminutes in declination from the location of the galaxy.
NGC 1386 is a spiral galaxy located in the constellation Eridanus. It is located at a distance of circa 53 million light years from Earth, which, given its apparent dimensions, means that NGC 1386 is about 50,000 light years across. It is a Seyfert galaxy, the only one in Fornax Cluster.
NGC 4074 is a peculiar lenticular galaxy located 310 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 27, 1785 and is a member of the NGC 4065 Group.
NGC 973 is a giant spiral galaxy located in the constellation Triangulum. It is located at a distance of circa 200 million light-years from Earth, which, given its apparent dimensions, means that NGC 973 is about 230,000 light years across. It was discovered by Lewis Swift on October 30, 1885.
NGC 931 is a spiral galaxy located in the constellation Triangulum. It is located at a distance of circa 200 million light-years from Earth, which, given its apparent dimensions, means that NGC 931 is about 200,000 light years across. It was discovered by Heinrich d'Arrest on September 26, 1865. It is classified as a Seyfert galaxy.
NGC 3393 is a barred spiral galaxy located in the constellation Hydra. It is located at a distance of circa 180 million light-years from Earth, which, given its apparent dimensions, means that NGC 3393 is about 140,000 light-years across. It was discovered by John Herschel on March 24, 1835. It is a Type II Seyfert galaxy, known to host two supermassive black holes, which are the nearest known pair of supermassive black holes to Earth.
NGC 4324 is a lenticular galaxy located about 85 million light-years away in the constellation Virgo. It was discovered by astronomer Heinrich d'Arrest on March 4, 1862. NGC 4324 has a stellar mass of 5.62 × 1010M☉, and a baryonic mass of 5.88 × 1010M☉. The galaxy's total mass is around 5.25 × 1011M☉. NGC 4324 is notable for having a ring of star formation surrounding its nucleus. It was considered a member of the Virgo II Groups until 1999, when its distance was recalculated and it was placed in the Virgo W Group.
NGC 7172 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 110 million light years from Earth, which, given its apparent dimensions, means that NGC 7172 is about 100,000 light years across. It was discovered by John Herschel on September 23, 1834.
NGC 5506 is a spiral galaxy located in the constellation Virgo. It is located at a distance of about 75 million light years from Earth, which, given its apparent dimensions, means that NGC 5506 is about 80,000 light years across. It was discovered by William Herschel on April 15, 1787. It is a Seyfert galaxy.
Markarian 590, also known as NGC 863, NGC 866, and NGC 885, is a spiral galaxy located in the constellation Cetus. It is located at a distance of about 300 million light years from Earth, which, given its apparent dimensions, means that NGC 863 is about 110,000 light years across. It is a change looking Seyfert galaxy.
NGC 5135 is a barred spiral galaxy located in the constellation Hydra. It is located at a distance of about 200 million light years from Earth. It was discovered by John Herschel on May 8, 1834. It is a Seyfert galaxy.
NGC 5953 is a peculiar spiral galaxy in the constellation Serpens. The galaxy lies about 80 million light years away from Earth, which means, given its apparent dimensions, that NGC 5953 is approximately 35,000 light years across. It was discovered by William Herschel on April 17, 1784. NGC 5953 interacts with NGC 5954 forming a pair known as Arp 91.
NGC 7682 is a barred spiral galaxy in the constellation Pisces. It is located at a distance of about 180 million light years from Earth, which, given its apparent dimensions, means that NGC 7682 is about 65,000 light years across. It was discovered by Heinrich d'Arrest on September 23, 1864.