NGC 4861, also known as Arp 266, is a galaxy in the constellation Canes Venatici. It was discovered by William Herschel on May 1, 1785.[4]
| NGC 4861 | |
|---|---|
 Hubble Space Telescope image of NGC 4861, taken using the Advanced Camera for Surveys | |
| Observation data (J2000 epoch) | |
| Constellation | Canes Venatici |
| Right ascension | 12h 59m 02.340s[1] |
| Declination | +34° 51′ 33.98″[1] |
| Redshift | 0.002785[2] |
| Heliocentric radial velocity | 835[2] |
| Distance | 34.77 ± 15.99 Mly (10.662 ± 4.903 Mpc)[2] |
| Group or cluster | Virgo Cluster |
| Apparent magnitude (V) | 12.32 |
| Apparent magnitude (B) | 12.90 |
| Characteristics | |
| Type | SB(s)m[2] Im/BCD |
| Apparent size (V) | 0.797′ × 0.692′[1] |
| Other designations | |
| Arp 266, UGC 8098, MCG+06-29-003, PGC 44536[3] | |
Morphological classification of NGC 4861 has proved relatively difficult. Its mass, size, and rotational velocity are consistent with it being a spiral galaxy. However, due to its highly irregular shape, it may also be classified as a dwarf irregular galaxy.[5] In fact, since dwarf galaxies are less massive and have lower gravitational potentials, gases and other material for star formation can move within them much faster, causing the galaxy to become a specific type of starburst galaxy, called a blue compact dwarf galaxy.[5][3] It has also been described as a "comet-like" galaxy due to its resemblance to a comet.[6]
Two ultraluminous X-ray sources (ULXs) have been found within NGC 4861. The first, NGC 4861 X1, is associated with a dense H II region. The second, NGC 4861 X2, seems to be within a small star cluster near the "comet head" of NGC 4861. Assuming it is a star cluster, it has a mass of 400±80 M☉ and an age of 5 million years. Compared to other star clusters with which ULXs are associated, its mass is quite low.[6]
See also
editReferences
edit- ^ a b c Skrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W.; Chester, Thomas; Elias, Jonathan H.; Huchra, John P.; Liebert, James W.; Lonsdale, Carol J.; Monet, David G.; Price, Stephan; Seitzer, Patrick; Jarrett, Thomas H.; Kirkpatrick, J. Davy; Gizis, John E.; Howard, Elizabeth V.; Evans, Tracey E.; Fowler, John W.; Fullmer, Linda; Hurt, Robert L.; Light, Robert M.; Kopan, Eugene L.; Marsh, Kenneth A.; McCallon, Howard L.; Tam, Robert; Van Dyk, Schuyler D.; Wheelock, Sherry L. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi:10.1086/498708. ISSN 0004-6256. S2CID 18913331.
- ^ a b c d "NED results for object NGC 4861". National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 4 February 2017.
- ^ a b "NGC 4861". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 February 2017.
- ^ Courtney Seligman. "New General Catalog Objects: NGC 4500 - 4599". Retrieved 4 February 2017.
- ^ a b "Starbirth with a chance of winds?". www.spacetelescope.org. Retrieved 4 February 2017.
- ^ a b Ela, M Ozdogan; Akyuz, A.; Aksaker, N.; Avdan, S.; Oralhan, I Akkaya; Vinokurov, A.; Allak, S.; Solovyeva, Y.; Atapin, K.; Bizyaev, D. (2021). "Optical counterparts of ULXs in two dwarf galaxies: NGC 4861 and NGC 4449". Monthly Notices of the Royal Astronomical Society. 505: 771–782. arXiv:2105.02302. doi:10.1093/mnras/stab1321.
External links
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Media related to NGC 4861 at Wikimedia Commons
