NGC 613 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Sculptor |
Right ascension | 01h 34m 18.235s [3] |
Declination | –29° 25′ 06.56″ [3] |
Heliocentric radial velocity | +1,487 [4] |
Distance | 67.5 Mly (20.7 Mpc) [5] |
Apparent magnitude (V) | 10.0 [6] |
Characteristics | |
Type | SBbc(rs) [7] |
Apparent size (V) | 5′.2 × 2′.6 [6] |
Other designations | |
MCG -05-04-044, PGC 5849 [8] |
NGC 613 is a barred spiral galaxy located 67 million light years away in the southern constellation of Sculptor. [5] [9] This galaxy was discovered in 1798 by German-English astronomer William Herschel, then re-discovered and catalogued by Scottish astronomer James Dunlop. It was first photographed in 1912, which revealed the spiral form of the nebula. [6] During the twentieth century, radio telescope observations showed that a linear feature in the nucleus was a relatively strong source of radio emission. [10]
NGC 613 is inclined by an angle of 37° to the line of sight from the Earth along a position angle of 125°. [12] The morphological classification of NGC 613 is SBbc(rs), [7] indicating that it is a spiral galaxy with a bar across the nucleus (SB), a weak inner ring structure circling the bar (rs), and moderate to loosely wound spiral arms (bc). [13] The bar is relatively broad but irregular in profile with a position angle that varies from 115–124° and dust lanes located along the leading edges. Star formation is occurring at the ends of the bar and extending along the well-defined spiral arms. The central bulge is readily apparent, with a radius of 14″. [12]
The classification of the nucleus is of type HII, indicating a match to the spectrum of an H II region. Near the core, the stars have a velocity dispersion of 136 ± 20 km/s. The nucleus is a source of radio emission with the form of an inner ring with a radius of about 1,100 ly (350 pc) and a linear feature that is perhaps perpendicular to it. The latter consists of three discrete blobs spanning approximately 2,000 ly (600 pc). [14] Observations suggest the presence of a supermassive black hole at the core with a mass in the range (1.9–9.6) × 107 times the mass of the Sun. [7]
On September 20, 2016, Argentinian amateur astronomer Victor Buso captured supernova SN 2016gkg in NGC 613, just as it was starting to erupt. [15] [16] This was a type IIb supernova, a supernova that initially shows a hydrogen envelope like a type II supernova, [15] but later loses the hydrogen lines in its spectrum to appear like a type Ib supernova. It showed the double peak that is common to many type IIb supernovae, rising to around magnitude 15.5 shortly after discovery and then again about 20 days later. The progenitor star has been identified in Hubble Space Telescope images from before its collapse, and it is likely to have been a yellow supergiant. [17]
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 Pinwheel Galaxy is a face-on 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 61 is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet. Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 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 Whirlpool Galaxy, also known as Messier 51a (M51a) or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy. It is 7.22 megaparsecs away and 23.58 kiloparsecs (76,900 ly) in diameter.
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 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 June 14, 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.
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.
Messier 96 is an intermediate spiral galaxy about 31 million light-years away in the constellation Leo.
Messier 108 is a barred spiral galaxy about 28 million light-years away from Earth in the northern constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the Earth, this galaxy is seen almost edge-on.
NGC 7331, also known as Caldwell 30, is an unbarred spiral galaxy about 40 million light-years (12 Mpc) away in the constellation Pegasus. It was discovered by William Herschel in 1784. NGC 7331 is the brightest galaxy in the field of a visual grouping known as the NGC 7331 Group of galaxies. In fact, the other members of the group, NGC 7335, 7336, 7337 and 7340, lie far in the background at distances of approximately 300-350 million light years.
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 2997 is a face-on unbarred spiral galaxy about 40 million light-years away in the faint southern constellation of Antlia. It was discovered March 4, 1793 by German-born astronomer William Herschel. J. L. E. Dreyer described it as, "a remarkable object, very faint, very large, very gradually then very suddenly bright middle and 4 arcsec nucleus. This is the brightest galaxy of the NGC 2997 group of galaxies, and was featured on the cover of the first edition of Galactic Dynamics by James Binney and Scott Tremaine.
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 5371 is a face-on spiral galaxy in the northern constellation Canes Venatici. It was discovered on January 14, 1788 by German-British astronomer William Herschel. The nearby NGC 5390 appears to be a duplicate entry for NGC 5371, since there is nothing at the former's position. NGC 5371 has an apparent magnitude of 11.3 and an angular size of 4.4′ × 3.5′. It is located at a distance of 129.5 ± 32.4 million light-years (39.70 ± 9.92 Mpc) from the Milky Way, and is receding with a heliocentric radial velocity of 2,552 km/s. The galaxy appears to be weakly interacting with the nearby, equidistant Hickson 68 group of galaxies, and thus may be a member. Collectively, they are sometimes dubbed the Big Lick galaxy group, after the city of Roanoke, Virginia.
NGC 7319 is a highly distorted barred spiral galaxy that is a member of the compact Stephan's Quintet group located in the constellation Pegasus, some 311 megalight-years distant from the Milky Way. The galaxy's arms, dust and gas have been highly disturbed as a result of the interaction with the other members of the Quintet. Nearly all of the neutral hydrogen has been stripped from this galaxy, most likely as a result of a collision with NGC 7320c some 100 million years ago. A pair of long, parallel tidal tails extend southward from NGC 7319 in the direction of NGC 7320c, and is undergoing star formation.
NGC 2770 is a spiral galaxy in the northern constellation of Lynx, near the northern constellation border with Cancer. It was discovered by German-born astronomer William Herschel on December 7, 1785. J. L. E. Dreyer described it as, "faint, large, much extended 150°, mottled but not resolved, 2 stars to north". NGC 2770 was the target for the first binocular image produced by the Large Binocular Telescope.
NGC 7424 is a barred spiral galaxy located 37.5 million light-years away in the southern constellation Grus. Its size makes it similar to our own galaxy, the Milky Way. It is called a "grand design" galaxy because of its well defined spiral arms. Two supernovae and two ultraluminous X-ray sources have been discovered in NGC 7424.
NGC 6118 is a grand design spiral galaxy located 83 million light-years away in the constellation Serpens. It measures roughly 110,000 light-years across; about the same as our own galaxy, the Milky Way. Its shape is classified as "SA(s)cd," meaning that it is unbarred and has several rather loosely wound spiral arms. The large numbers of bright bluish knots are active star-forming regions where some very luminous and young stars can be perceived.
NGC 5584 is a barred spiral galaxy in the constellation Virgo. It was discovered July 27, 1881 by American astronomer E. E. Barnard. Distance determination using Cepheid variable measurements gives an estimate of 75 million light years, whereas the tip of the red-giant branch approach yields a distance of 73.4 million light years. It is receding with a heliocentric radial velocity of 1,637 km/s. It is a member of the Virgo III Groups, a series of galaxies and galaxy clusters strung out to the east of the Virgo Supercluster of galaxies.
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.