Messier 77

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Messier 77
Messier 77 spiral galaxy by HST.jpg
Hubble Space Telescope image of M77 core
Observation data (J2000 epoch)
Right ascension02h 42m 40.771s[1]
Declination−00° 00′ 47.84″[1]
Redshift1,137±3 km/s[2]
Distance47 Mly (14.4 Mpc)[3]
Apparent magnitude (V)9.6[2]
Mass~1×109[5] M
Apparent size (V)7′.1 × 6′.0[2]
Notable featuresOne of the biggest galaxies
of Messier's catalog.
Inclination estimated to be 40°.[3]
Other designations
Cetus A, Arp 37, M77, NGC 1068, PGC 10266, UGC 2188[6]

Messier 77 or M77, also known as NGC 1068, is a barred spiral galaxy about 47 million light-years away in the constellation Cetus. Messier 77 was discovered by Pierre Méchain in 1780, who originally described it as a nebula. Méchain then communicated his discovery to Charles Messier, who subsequently listed the object in his catalog.[7] Both Messier and William Herschel described this galaxy as a star cluster.[7] Today, however, the object is known to be a galaxy.

The morphological classification of NGC 1068 in the De Vaucouleurs system is (R)SA(rs)b,[4] where the '(R)' indicates an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'b' says the spiral arms are moderately wound.[8] Ann et al. (2015) gave it a class of SAa,[9] suggesting tightly wound arms. However, infrared images of the inner part of the galaxy reveal a prominent bar not seen in visual light,[10] and for this reason it is now considered a barred spiral.[11]

Messier 77 is an active galaxy with an Active Galactic Nucleus (AGN), which is obscured from view by astronomical dust at visible wavelengths. The diameter of the molecular disk and hot plasma associated with the obscuring material was first measured at radio wavelengths by the VLBA and VLA. The hot dust around the nucleus was subsequently measured in the mid-infrared by the MIDI instrument at the VLTI. It is the brightest[12] and one of the closest and best-studied[11] type 2 Seyfert galaxies,[3] forming a prototype of this class.[11]

X-ray source 1H 0244+001 in Cetus has been identified as Messier 77.[13] Only one supernova has been detected in Messier 77. The supernova, named SN 2018ivc, was discovered on 24 November 2018 by the DLT40 Survey. It is a type II supernova, and at discovery it was 15th magnitude and brightening.[14]

A star, of like 9th magnitude, which is less than M77's apparent angular width to the east, is HIP 12668. This has a parallax in milliarcseconds of 3.5640 ±0.0394, meaning it is about 915 light years away, in our own galaxy.[6]



  1. ^ a b Skrutskie, M. F.; et al. (February 2006), "The Two Micron All Sky Survey (2MASS)", The Astronomical Journal, 131 (2): 1163–1183, Bibcode:2006AJ....131.1163S, doi:10.1086/498708.
  2. ^ a b c "NASA/IPAC Extragalactic Database". Results for NGC 1068. Retrieved 18 November 2006.
  3. ^ a b c R. J. Rand; J. F. Wallin (2004). "Pattern Speeds BIMA-SONG Galaxies with Molecule-Dominated ISMs Using the Tremaine-Weinberg Method". The Astrophysical Journal. 614 (1): 142–157. arXiv:astro-ph/0406426. Bibcode:2004ApJ...614..142R. doi:10.1086/423423. S2CID 17095983.
  4. ^ a b de Vaucouleurs, G.; et al. (1991), Third reference catalogue of bright galaxies, 9, New York: Springer-Verlag.
  5. ^ "Messier 77: Cetus A - Messier Objects". Retrieved 18 April 2018.
  6. ^ a b "BD-00 413". sim-id. Retrieved 13 February 2021.
  7. ^ a b K. G. Jones (1991). Messier's Nebulae and Star Clusters (2nd ed.). Cambridge University Press. ISBN 978-0-521-37079-0.
  8. ^ de Vaucouleurs, Gérard (April 1963), "Revised Classification of 1500 Bright Galaxies", Astrophysical Journal Supplement, 8: 31, Bibcode:1963ApJS....8...31D, doi:10.1086/190084.
  9. ^ 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, S2CID 119253507.
  10. ^ Thronson, Harley A., Jr.; et al. (1 August 1989), "Near-infrared image of NGC 1068 - Bar-driven star formation and the circumnuclear composition", Astrophysical Journal, Part 1, 343: 158–168, Bibcode:1989ApJ...343..158T, doi:10.1086/167693.
  11. ^ a b c Alexander, Tal; Lutz, Dieter; Sturm, Eckhard; Genzel, Reinhard; Sternberg, Amiel; Netzer, Hagai (June 2000), "Infrared Spectroscopy of NGC 1068: Probing the Obscured Ionizing AGN Continuum", The Astrophysical Journal, 536 (2): 710–717, arXiv:astro-ph/0002107, Bibcode:2000ApJ...536..710A, doi:10.1086/308973, S2CID 15617708.
  12. ^ de Vaucouleurs, Gérard (1973). "Southern Galaxies.VI. Luminosity Distribution in the Seyfert Galaxy NGC 1566". Astrophysical Journal. 181: 31–50. Bibcode:1973ApJ...181...31D. doi:10.1086/152028.
  13. ^ Wood KS; Meekins JF; Yentis DJ; Smathers HW; McNutt DP; Bleach RD (1984). "The HEAO A-1 X-ray source catalog". Astrophysical Journal Supplement Series. 56 (12): 507–649. Bibcode:1984ApJS...56..507W. doi:10.1086/190992.
  14. ^ King, Bob (29 November 2018). "Supernova Discovered in the Bright Galaxy M77". Sky & Telescope. Retrieved 30 November 2018.
  15. ^ "Dazzling galaxy Messier 77". Retrieved 5 July 2017.

External links[edit]

Coordinates: Sky map 02h 42m 40.7s, −00° 00′ 48″