Whirlpool galaxy

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Whirlpool galaxy
Messier51 sRGB.jpg
Whirlpool Galaxy (M51A or NGC 5194). The smaller object in the upper right is M51B or NGC 5195. Credit: NASA/ESA
Observation data (J2000 epoch)
Constellation Canes Venatici[1]
Right ascension 13h 29m 52.7s[2]
Declination +47° 11′ 43″[2]
Redshift 463 ± 3 km/s[2]
Distance 23 ± 4 Mly (7.1 ± 1.2 Mpc)[3][4]
Type SA(s)bc pec[2]
Apparent dimensions (V) 11′.2 × 6′.9[2]
Apparent magnitude (V) 8.4[5]
Notable features Interacting with NGC 5195[6]
Other designations
Question Mark Galaxy,[2] Rosse's Galaxy,[2] M51a,[2] NGC 5194,[2] UGC 8493,[2] PGC 47404,[2] VV 001a,[2] VV 403,[2] Arp 85,[2] GC 3572[2]
See also: Galaxy, List of galaxies

The Whirlpool galaxy, is also known as Messier 51a, M51a, or NGC 5194. It is a large galaxy with large spirals, with a smaller companion galaxy. They have been through a collision,[7] and are still interacting.[6]

The whirlpool was the first galaxy to be classified as a spiral galaxy.[8] Different methods put its distance as between 15 to 35 million light-years. Recently it was estimated to be 23 ± 4 million light-years from the Milky Way.[3] Messier 51 is one of the best known galaxies in the sky.[9]

Its spirals are so impressive that it is sometimes called a "grand design" spiral galaxy.[10] It has an active galactic nucleus,[11] no doubt fuelled by a massive black hole.

The galaxy and its companion, NGC 5195, are easily seen by amateur astronomers, in the constellation Canes Venatici. The two galaxies can be seen with binoculars.[12] The Whirlpool galaxy is also a popular target for professional astronomers. They study its galaxy structure (particularly the spiral arms) and galaxy interactions.

References[change | change source]

  1. Dreyer J.L.E. 1988. In Sinnott R.W, ed. The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters. Sky Publishing Corporation/Cambridge University Press. ISBN 0-933346-51-4. 
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 "NASA/IPAC Extragalactic Database". Results for NGC 5194. Retrieved 2006-12-06. 
  3. 3.0 3.1 Takáts K. & Vinkó J. 2006.. "Distance estimate and progenitor characteristics of SN 2005cs in M51". Monthly Notices of the Royal Astronomical Society 372 (4): 1735. doi:10.1111/j.1365-2966.2006.10974.x. 
  4. "Distance Results for MESSIER 051". NASA/IPAC Extragalactic Database. Retrieved 2011-06-06. 
  5. "M51". SEDS.org. 
  6. 6.0 6.1 Arp H. 1966 Atlas of peculiar galaxies. Astrophysical Journal Supplement 14, 1–20. [1]
  7. When galaxies collide, they actually move through each other. This causes gravitational effects, and leads to an increase in star formation.
  8. "Whirlpool Galaxy: First Spiral Galaxy". Universe for Facts. Retrieved 21 December 2014. 
  9. Scalzi, John 2003. The Rough Guide to the Universe. Rough Guides. p. 250. ISBN 1-85828-939-4. 
  10. Elmegreen D.M. & Elmegreen B.G. 1987. "Arm classifications for spiral galaxies". Astrophysical Journal 314: 3–9. doi:10.1086/165034. 
  11. Matsushita, Satoki; Muller, Sebastien & Lim, Jeremy 2007. Jet-disturbed molecular gas near the Seyfert 2 nucleus in M51. doi:10.1051/0004-6361:20067039. https://arxiv.org/abs/0704.0947. Retrieved 16 February 2014. 
  12. Nemiroff, Robert & Bonnell, Jerry 2000. "M51: The Whirlpool Galaxy". Astronomy Picture of the Day. NASA. Retrieved 2007-04-22.