NGC 4861
Hubble Space Telescope image of NGC 4861, taken using the Advanced Camera for Surveys
Observation data (J2000 epoch)
ConstellationCanes Venatici
Right ascension12h 59m 02.340s[1]
Declination+34° 51′ 33.98″[1]
Redshift0.002785[2]
Heliocentric radial velocity835[2]
Distance34.77 ± 15.99 Mly (10.662 ± 4.903 Mpc)[2]
Group or clusterVirgo Cluster
Apparent magnitude (V)12.32
Apparent magnitude (B)12.90
Characteristics
TypeSB(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]

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]

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

References

  1. ^ 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.
  2. ^ a b c d "NED results for object NGC 4861". National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 4 February 2017.
  3. ^ a b "NGC 4861". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 February 2017.
  4. ^ Courtney Seligman. "New General Catalog Objects: NGC 4500 - 4599". Retrieved 4 February 2017.
  5. ^ a b "Starbirth with a chance of winds?". www.spacetelescope.org. Retrieved 4 February 2017.
  6. ^ 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

Galaxies
Astronomical catalogs
Constellation of Canes Venatici
New General Catalogue 4500 to 4999
Categories