NGC 3642 | |
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Observation data (J2000 epoch) | |
Constellation | Ursa Major |
Right ascension | 11h 22m 17.9s [1] |
Declination | 59° 04′ 28″ [1] |
Redshift | 1571 ± 3 km/s [1] |
Distance | 27 ± 35 Mly (8.4 ± 10.7 Mpc) [1] |
Apparent magnitude (V) | 10.8 |
Characteristics | |
Type | SA(r)bc [1] |
Apparent size (V) | 1.8′ × 1.5′ [1] |
Other designations | |
UGC 6385, MCG +10-16-128, PGC 34889 [1] |
NGC 3642 is a spiral galaxy in the constellation Ursa Major. The galaxy has a low-ionization nuclear emission-line region. It is located at a distance of circa 30 million light years from Earth, which, given its apparent dimensions, means that NGC 3642 is about 50,000 light years across. The galaxy is characterised by an outer pseudoring, which was probably formed after the accretion of a gas rich dwarf galaxy. [2]
NGC 3642 is a spiral galaxy without a bar. [2] In the nucleus there is a supermassive black hole with an estimated mass of 26-31 million M⊙, based on the intrinsic velocity dispersion as measured by the Hubble Space Telescope, [3] or 15 million M⊙, based on the bulge luminosities in near-infrared Ks-band. [4]
Around the nucleus, a one-armed spiral forms a ring, and it is possible that it leads material towards the nucleus. The nucleus is surrounded by an inner flocculent spiral. The outer part of the spiral forms a pseudoring that extends for about half a circle. The outer part of the spiral is warped, while its main part features an ordinary differentially rotating disk. The HI gas is also warped and extends further on the western side. [2]
The galaxy belongs to the NGC 3642 group [5] (also known as the NGC 3610 group), a galaxy group that also includes NGC 3610, NGC 3619, NGC 3669, NGC 3674 and NGC 3683. Other nearby galaxies include NGC 3440, NGC 3445, NGC 3458, NGC 3543 and NGC 3613. [6]
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 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.
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.
Messier 106 is an intermediate spiral galaxy in the constellation Canes Venatici. It was discovered by Pierre Méchain in 1781. M106 is at a distance of about 22 to 25 million light-years away from Earth. M106 contains an active nucleus classified as a Type 2 Seyfert, and the presence of a central supermassive black hole has been demonstrated from radio-wavelength observations of the rotation of a disk of molecular gas orbiting within the inner light-year around the black hole. NGC 4217 is a possible companion galaxy of Messier 106. Besides the two visible arms, it has two "anomalous arms" detectable using an X-ray telescope.
NGC 5548 is a Type I Seyfert galaxy with a bright, active nucleus. This activity is caused by matter flowing onto a 65 million solar mass (M☉) supermassive black hole at the core. Morphologically, this is an unbarred lenticular galaxy with tightly-wound spiral arms, while shell and tidal tail features suggest that it has undergone a cosmologically-recent merger or interaction event. NGC 5548 is approximately 245 million light years away and appears in the constellation Boötes. The apparent visual magnitude of NGC 5548 is approximately 13.3 in the V band.
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 613 is a barred spiral galaxy located 67 million light years away in the southern constellation of Sculptor. 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. During the twentieth century, radio telescope observations showed that a linear feature in the nucleus was a relatively strong source of radio emission.
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 2681 is a lenticular galaxy in the constellation Ursa Major. The galaxy lies 50 million light years away from Earth, which means, given its apparent dimensions, that NGC 2681 is approximately 55,000 light years across. NGC 2681 has an active galactic nucleus and it is a type 3 Seyfert galaxy. Its nucleus is also a low-ionization nuclear emission-line region.
NGC 3675 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of circa 50 million light years from Earth, which, given its apparent dimensions, means that NGC 3675 is about 100,000 light years across. It was discovered by William Herschel in 1788.
NGC 3081 is a barred lenticular ring galaxy in the constellation of Hydra. NGC 3081 is located about 85 million light-years away from Earth, which means, given its apparent dimensions, that NGC 3081 is approximately 60,000 light-years across. It is a type II Seyfert galaxy, characterised by its bright nucleus. It was discovered by William Herschel on 21 December 1786.
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 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.
NGC 541 is a lenticular galaxy located in the constellation Cetus. It is located at a distance of about 230 million light years from Earth, which, given its apparent dimensions, means that NGC 541 is about 130,000 light years across. It was discovered by Heinrich d'Arrest on October 30, 1864. It is a member of the Abell 194 galaxy cluster and is included in the Atlas of Peculiar Galaxies in the category galaxies with nearby fragments. NGC 541 is a radio galaxy of Fanaroff–Riley class I, also known as 3C 40A.
NGC 5965 is a spiral galaxy located in the constellation Draco. It is located at a distance of circa 150 million light years from Earth, which, given its apparent dimensions, means that NGC 5965 is about 260,000 light years across. It was discovered by William Herschel on May 5, 1788.
NGC 6951 is a barred spiral galaxy located in 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 2273 is a barred spiral galaxy located in the constellation Lynx. It is located at a distance of circa 95 million light years from Earth, which, given its apparent dimensions, means that NGC 2273 is about 100,000 light years across. It was discovered by Nils Dunér on September 15, 1867.
NGC 2964 is an intermediate spiral galaxy located in the constellation Leo. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 2964 is about 60,000 light years across. It was discovered by William Herschel on December 7, 1785.
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 2911 is a peculiar lenticular galaxy in the constellation Leo. The galaxy lies about 145 million light years away from Earth, which means, given its apparent dimensions, that NGC 2911 is approximately 165,000 light years across. It was discovered by William Herschel on March 11, 1784.