NGC 3656 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Ursa Major |
Right ascension | 11h 23m 38.7s [1] |
Declination | +53° 50′ 32″ [1] |
Redshift | 0.009640 ± 0.000037 [1] |
Heliocentric radial velocity | 2,890 ± 11 km/s [1] |
Distance | 139 Mly (42.6 Mpc) [1] |
Apparent magnitude (V) | 12.3 [2] |
Characteristics | |
Type | (R')I0: pec [1] |
Apparent size (V) | 1.6′ × 1.6′ [1] |
Notable features | Merger remnant |
Other designations | |
UGC 6403, Arp 155, VV 22a, CGCG 268-029, MCG +09-19-063, PGC 34989 [1] |
NGC 3656 is a peculiar galaxy formed by the collision of two galaxies in the constellation of Ursa Major. It is located about 135 million light years away from Earth, which means, given its apparent dimensions, that NGC 3656 is approximately 70,000 light years across. It was discovered by William Herschel on April 14, 1789. [3]
NGC 3656 is a galaxy merger, created by the collision of two disk galaxies. The merger has created shells around the galaxy and two faint tidal tails. [4] The first tail emanates from a position angle of 260° and after bends to the north-northwest. Its total extent is about 180 arcseconds, towards a dwarf galaxy, and maybe even more, towards a second dwarf galaxy. Its width is 15 arcseconds. The other tail lies at the north-northeast part of the galaxy and is not as well defined as the other. [4] Other characteristics of the galaxy include the presence of a condensation at the south part of the galaxy connected with the rest of the galaxy with a ring-like feature and is associated with a bright shell. [4] [5]
A prominent feature of the galaxy is a dark lane running across the minor axis of the galaxy, similar to that observed in Centaurus A. [5] At the centre of the galaxy a warped molecular gas disk extending for about 7 kiloparsecs has been observed in H I imaging, with an estimated mass of 2×109M☉. [6] The inner part of the disk features more intense star formation. [7] The total star formation rate of the galaxy is estimated to be 1.1 M☉ per year. [8]
The nucleus of NGC 3656 has been found to rotate around an axis that is almost perpendicular to the rotation axis of the rest of the galaxy, which is another indication of a galaxy merger. [9]
Two supernovae have been observed in NGC 3656:
NGC 3656 is the foremost member in a galaxy group known as the NGC 3656 group. Another member is UGC 6422. A bit further away lies the galaxy NGC 3549 with its group. [15] Five dwarf galaxies with estimated masses between 2×108 and 2×109M☉ have been detected in HI imaging around the galaxy and are probably in the process of being accreted by NGC 3656. [6]
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 520, also known as the Flying Ghost, is a pair of colliding spiral galaxies about 105 million light-years away in the constellation Pisces. They were discovered by astronomer William Herschel on 13 December 1784.
NGC 5253 is an irregular galaxy in the constellation Centaurus. It was discovered by William Herschel on 15 March 1787.
NGC 5033 is an inclined spiral galaxy located in the constellation Canes Venatici. Distance estimates vary from between 38 and 60 million light years from the Milky Way. The galaxy has a very bright nucleus and a relatively faint disk. Significant warping is visible in the southern half of the disk. The galaxy's relatively large angular size and relatively high surface brightness make it an object that can be viewed and imaged by amateur astronomers. The galaxy's location relatively near Earth and its active galactic nucleus make it a commonly studied object for professional astronomers.
NGC 4666 is a spiral galaxy in the equatorial constellation of Virgo, located at a distance of approximately 55 megalight-years from the Milky Way. It was discovered by the German-born astronomer William Herschel on February 22, 1784. 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. John L. E. Dreyer described it as "bright, very large, much extended 45°±, pretty suddenly brighter middle". It is a member of an interacting system with NGC 4668 and a dwarf galaxy, and belongs to a small group that also includes NGC 4632.
NGC 4651 is a spiral galaxy located in the constellation of Coma Berenices that can be seen with amateur telescopes, at a distance not well determined that ranges from 35 million light years to 72 million light years. It was discovered by German-British astronomer William Herschel on 30 December 1783.
NGC 2748 is a spiral galaxy in the northern circumpolar constellation of Camelopardalis, located at a distance of 61.3 megalight-years from the Milky Way. It was discovered September 2, 1828 by John Herschel. The morphological classification of SAbc indicates this is an unbarred spiral with moderate to loosely-wound spiral arms. It is a disk-like peculiar galaxy with a stellar shell that is rotating about the main galactic axis. This shell was most likely formed through the capture and disruption of a dwarf companion. The galactic nucleus likely contains a supermassive black hole with a mass of 4.4+3.5
−3.6×107 M☉, or 44 million times the mass of the Sun.
NGC 1003 is a spiral galaxy at the western edge of the Perseus constellation. It is located at a distance of about 36 million light years from the Milky Way and is receding with a heliocentric radial velocity of 624 km/s. This galaxy was discovered by the Anglo-German astronomer William Herschel on October 6, 1784, who described it as "pretty faint, large, extended 90°±, much brighter middle, mottled but not resolved". It is a member of the NGC 1023 group 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 3631 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of about 35 million light years from Earth, which, given its apparent dimensions, means that NGC 3631 is about 60,000 light years across. It was discovered by William Herschel on April 14, 1789. It is a grand design spiral galaxy seen face on.
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 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 5982 is an elliptical galaxy located in the constellation Draco. It is located at a distance of circa 130 million light years from Earth, which, given its apparent dimensions, means that NGC 5982 is about 100,000 light years across. It was discovered by William Herschel on May 25, 1788.
NGC 1380 is a lenticular galaxy located in the constellation Fornax. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 1380 is about 85,000 light years across. It was discovered by James Dunlop on September 2, 1826. It is a member of the Fornax Cluster.
NGC 6621 is an interacting spiral galaxy in the constellation Draco. It lies at a distance of about 260 million light-years. NGC 6621 interacts with NGC 6622, with their closest approach having taken place about 100 million years ago. The pair was discovered by Edward D. Swift and Lewis A. Swift on June 2, 1885. Originally NGC 6621 was assigned to the southeast galaxy, but now it refers to the northern one. NGC 6621 and NGC 6622 are included in the Atlas of Peculiar Galaxies as Arp 81 in the category "spiral galaxies with large high surface brightness companions".
NGC 7674 is a spiral galaxy located in the constellation Pegasus. It is located at a distance of about 350 million light years from Earth, which, given its apparent dimensions, means that NGC 7674 is about 125,000 light years across. It was discovered by John Herschel on August 16, 1830.
NGC 6907 is a spiral galaxy located in the constellation Capricornus. It is located at a distance of about 120 million light-years from Earth, which, given its apparent dimensions, means that NGC 6907 is about 115,000 light-years across. It was discovered by William Herschel on July 12, 1784. The total infrared luminosity of the galaxy is 1011.03 L☉, and thus it is categorised as a luminous infrared galaxy.
NGC 5363 is a lenticular galaxy located in the constellation Virgo. It is located at a distance of circa 65 million light years from Earth, which, given its apparent dimensions, means that NGC 5363 is about 100,000 light years across. It was discovered by William Herschel on January 19, 1784. It is a member of the NGC 5364 Group of galaxies, itself one of the Virgo III Groups strung out to the east of the Virgo Supercluster of galaxies.
NGC 4589 is an elliptical galaxy located in the Draco constellation. It was discovered by German-British astronomer William Herschel on November 22, 1797. This galaxy lies at a distance of 73.0 million light-years (22.39 Mpc) from the Milky Way, and is receding with a heliocentric radial velocity of 2,002 km/s. It is known by its designations PGC 42139 or UGC 7797.
NGC 4157 is a spiral galaxy in the constellation Ursa Major. The galaxy lies about 55 million light years away from Earth, which means, given its apparent dimensions, that NGC 4157 is approximately 125,000 light years across. It was discovered by William Herschel on March 9, 1788.