Messier 63

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Messier 63
M63 (NGC 5055).jpg
Spiral galaxy M63 (NGC 5055), imaged at 450 and 814 nm[1]
Observation data (J2000 epoch)
ConstellationCanes Venatici
Right ascension 13h 15m 49.27385s[2]
Declination+42° 01′ 45.7261″[2]
Redshift484 km/s[3]
Distance29.3 Mly (8.99 Mpc)[4]
Group or clusterM51 Group
Apparent magnitude (V)9.3[3]
Apparent size (V)12′.6 × 7′.2[3]
Other designations
M63, NGC 5055, PGC 46153, UGC 8334[3]
See also: Galaxy, List of galaxies

Messier 63 or M63, also known as NGC 5055 or the seldom-used Sunflower Galaxy,[6] is a spiral galaxy in the northern constellation of Canes Venatici. M63 was first discovered by the French astronomer Pierre Méchain then later verified by his colleague Charles Messier on June 14, 1779.[6] 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.[7]

This galaxy has a morphological classification of SAbc,[5] indicating a spiral shape with no central bar feature and moderate to loosely wound arms. There is a general lack of large scale continuous spiral structure in visible light, a galaxy form known as flocculent. However, when observed in the near infrared a symmetric, two-arm structure becomes apparent. Each arm wraps 150° around the galaxy and extends out to 13 kly (4 kpc) from the nucleus.[8]

M63 is an active galaxy with a LINER nucleus. This displays as an unresolved nuclear source wrapped in a diffuse emission. The latter is extended along a position angle of 110° and soft X-rays and H-alpha emission can be observed coming from along nearly the same direction.[9] The existence of a super massive black hole (SMBH) at the nucleus is uncertain; if it does exist, then the mass is estimated as (8.5±1.9)×108 M.[10]

Radio observations at 21-cm show the gaseous disk of M63 extending outward to a radius of 40 kpc (130 kly), well past the bright optical disk. This gas shows a symmetrical form that is warped in a pronounced manner, starting at a radius of 10 kpc (33 kly). The form suggests the dark matter halo of the galaxy is offset with respect to the inner region. The reason for the warp is unclear, but the position angle points toward the smaller companion galaxy, UGC 8313.[11]

The distance to M63, based upon the luminosity-distance measurement is 8.99 Mpc (29.3 Mly).[4] The radial velocity relative to the Local Group yields an estimate of 4.65 Mpc (15.2 Mly).[5] Estimates based on the Tully-Fisher relation range over 5.0–10.3 Mpc (16–34 Mly). The tip of the red-giant branch technique gives a distance of 8.87 ± 0.29 Mpc (28.93 ± 0.95 Mly).[12] M63 is part of the M51 Group, a group of galaxies that also includes M51 (the 'Whirlpool Galaxy').[13]

In 1971, a supernova with a magnitude of 11.8 appeared in one of the arms of M63. It was discovered May 24, 1971 and reached peak light around May 26.[14] The spectrum of SN 1971 I is consistent with a supernova of type I. However, the spectroscopic behavior appeared anomalous.[15]



  1. ^ Morrow, Ashley, ed. (September 11, 2015), Hubble Sees a Galactic Sunflower, NASA, retrieved 2018-11-30.
  2. ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  3. ^ a b c d "NASA/IPAC Extragalactic Database". Results for NGC 5055. Retrieved 2006-10-10.
  4. ^ a b Tully, R. Brent; et al. (August 2016), "Cosmicflows-3", The Astronomical Journal, 152 (2): 21, arXiv:1605.01765, Bibcode:2016AJ....152...50T, doi:10.3847/0004-6256/152/2/50, 50.
  5. ^ a b c Ann, H. B.; et al. (2015), "A Catalog of Visually Classified Galaxies in the Local (z ∼ 0.01) Universe", The Astrophysical Journal Supplement Series, 217 (2): 27–49, arXiv:1502.03545, Bibcode:2015ApJS..217...27A, doi:10.1088/0067-0049/217/2/27.
  6. ^ a b Garfinkle, Robert A. (1997), Star-Hopping: Your Visa to Viewing the Universe, Cambridge University Press, p. 258, ISBN 978-0521598897.
  7. ^ Jones, K. G. (1991), Messier's Nebulae and Star Clusters (2nd ed.), Cambridge: Cambridge University Press, ISBN 978-0-521-37079-0.
  8. ^ Thornley, Michele D. (September 1996), "Uncovering Spiral Structure in Flocculent Galaxies", Astrophysical Journal Letters, 469: L45, arXiv:astro-ph/9607041, Bibcode:1996ApJ...469L..45T, doi:10.1086/310250.
  9. ^ Masegosa, J.; et al. (March 2011), "The nature of nuclear Hα emission in LINERs", Astronomy & Astrophysics, 527: 28, arXiv:1011.0865, Bibcode:2011A&A...527A..23M, doi:10.1051/0004-6361/201015047, A23.
  10. ^ Graham, Alister W. (November 2008), "Populating the Galaxy Velocity Dispersion - Supermassive Black Hole Mass Diagram: A Catalogue of (Mbh, σ) Values", Publications of the Astronomical Society of Australia, 25 (4): 167–175, arXiv:0807.2549, Bibcode:2008PASA...25..167G, doi:10.1071/AS08013.
  11. ^ Battaglia, G.; et al. (February 2006), "ion{H}{i} study of the warped spiral galaxy NGC 5055: a disk/dark matter halo offset?", Astronomy and Astrophysics, 447 (1): 49–62, arXiv:astro-ph/0509382, Bibcode:2006A&A...447...49B, doi:10.1051/0004-6361:20053210.
  12. ^ McQuinn, Kristen. B. W.; et al. (August 2017), "Accurate Distances to Important Spiral Galaxies: M63, M74, NGC 1291, NGC 4559, NGC 4625, and NGC 5398", The Astronomical Journal, 154 (2): 13, arXiv:1706.06586, Bibcode:2017AJ....154...51M, doi:10.3847/1538-3881/aa7aad, 51.
  13. ^ Tikhonov, N. A.; et al. (September 2009), "Stellar content of the interacting galaxies of the M51 system", Astronomy Letters, 35 (9): 599–608, Bibcode:2009AstL...35..599T, doi:10.1134/S1063773709090035.
  14. ^ Barbon, R.; et al. (1973), "Observations of five supernovae 1970-71", Memorie della Società Astronomia Italiana, 44: 65, Bibcode:1973MmSAI..44...65B.
  15. ^ Deming, Drake; et al. (June 1973), "The Light Curve of Supernova 1971 I", Publications of the Astronomical Society of the Pacific, 85 (505): 321, Bibcode:1973PASP...85..321D, doi:10.1086/129462

External links[edit]

Coordinates: Sky map 13h 15m 49.3s, +42° 01′ 45″