Messier 77

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Messier 77
Messier 77 spiral galaxy by HST.jpg
Observation data (J2000 epoch)
Constellation Cetus
Right ascension 2h 42m 40.7s[1]
Declination −00° 00′ 48″[1]
Redshift 1137 ± 3 km/s[1]
Distance 47.0 Mly (14.4 Mpc)[2]
Type (R)SA(rs)b[1]
Apparent dimensions (V) 7′.1 × 6′.0[1]
Apparent magnitude (V) 9.6[1]
Notable features One of the biggest galaxies
of Messier's catalog.
Inclination estimated to be 40°.[2]
Other designations
Cetus A, M77, NGC 1068, UGC 2188, PGC 10266, Arp 37[1]
See also: Galaxy, List of galaxies

Messier 77 (also known as NGC 1068) is a barred spiral galaxy about 47 million light-years away in the constellation Cetus. 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[3] Seyfert galaxy and is of type 2.[2]

Messier 77's diameter is 170,000 light-years.

M77 with amateur telescope.

History[edit]

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.[4] Both Messier and William Herschel described this galaxy as a star cluster.[4] Today, however, the object is known to be a galaxy.

X-ray source[edit]

X-ray source 1H 0244+001 in Cetus has been identified as Messier 77 (NGC 1068, M77).[5]

References[edit]

  1. ^ a b c d e f g "NASA/IPAC Extragalactic Database". Results for NGC 1068. Retrieved 2006-11-18. 
  2. ^ 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: 142–157. arXiv:astro-ph/0406426. Bibcode:2004ApJ...614..142R. doi:10.1086/423423. 
  3. ^ 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. 
  4. ^ a b K. G. Jones (1991). Messier's Nebulae and Star Clusters (2nd ed.). Cambridge University Press. ISBN 0-521-37079-5. 
  5. ^ 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. 

External links[edit]

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