NGC 7013

NGC 7013
Hubble image of NGC 7013.
Observation data (J2000 epoch)
Constellation Cygnus
Right ascension 21h 03m 33.6s[1]
Declination 29° 53′ 51″[1]
Redshift 0.002598/779 km/s[1]
Distance 37/41.4 (estimated) Mly
Apparent magnitude (V) 12.40[1]
Characteristics
Type SA(r)0/a, LINER[1]
Size

~43,680

ly (diameter)
Apparent size (V) 4.0 × 1.4[1]
Other designations
UGC 11670, CGCG 491-2, IRAS 21014+2941, MCG 5-49-1, PGC 66003[1]

NGC 7013 is a relatively nearby spiral or lenticular galaxy[2][3] estimated to be around 37 to 41.4 million light-years away from Earth[4][5] in the constellation of Cygnus.[6] NGC 7013 was discovered by English astronomer William Herschel on July 17, 1784 and was also observed by his son, astronomer John Herschel on September 15, 1828.[7]

Physical characteristics

NGC 7013 is tilted 90° to the Earth's line of sight,[8] allowing its structure to be seen. However, NGC 7013 is classified as either as a spiral galaxy with tightly wound arms or as a lenticular galaxy.[2][9] NGC 7013 is also considered part of a class of galactic nuclei that is defined by their spectral line emissions, called low-ionization nuclear emission-line region galaxies or LINERs.[9][10] The galaxy appears to have two rings in its structure. The inner ring appears to completely disconnect from the central bulge while the stars in the outer ring appear to have very little spiral pattern.[2] Optical images of NGC 7013 show that it has a small bulge[11] with a bright inner ring and a faint disk both crossed by dust lanes.[3] A longer exposure of the galaxy made by the Palomar Observatory-National Geographic Sky Survey shows an extended disk around the bulge and the inner ring. The disk shows little structure except for a faint, thin spiral-like feature running through the galaxy.[3]

HI distribution

The neutral atomic hydrogen distribution in NGC 7013 is mostly located in the two rings. In between the two rings there is a very low concentration of interstellar medium. The low level of neutral atomic hydrogen in the disk of NGC 7013 and the reddish color of the galaxy suggests that the gas content of the galactic disc has fallen below the threshold at which star formation is likely to take place. The small bulge-to-disk ratio and the slow rotation velocity show that NGC 7013 is a low-mass, low-density galaxy unlike the more luminous, typical lenticular galaxies. The galaxy may thus be a former late-type spiral galaxy which have exhausted most of its interstellar gas, either by star formation or by internal sweeping.[3]

See also

References

  1. 1 2 3 4 5 6 7 "NASA/IPAC Extragalactic Database". Results for NGC 7013. Retrieved 2017-05-21.
  2. 1 2 3 "AstroImaging by Kent Biggs". www.kentbiggs.com. Retrieved 2017-05-21.
  3. 1 2 3 4 "Distribution and motions of atomic hydrogen in lenticular galaxies II. NGC 7013" (PDF). Astronomy and Astrophysics. 133: 127. 27 October 1983. Bibcode:1984A&A...133..127S.
  4. ↑ Sanders, R. H.; Noordermeer, E. (2007). "Confrontation of Modified Newtonian Dynamics with the rotation curves of early-type disc galaxies". Monthly Notices of the Royal Astronomical Society. 379 (2): 702. arXiv:astro-ph/0703352. Bibcode:2007MNRAS.379..702S. doi:10.1111/j.1365-2966.2007.11981.x.
  5. ↑ B.A. Williams, F. J. Kerr (21 December 1977). "H I OBSERVATIONS OF ELLIPTICAL GALAXIES". The Astrophysical Journal. 222: 15. Bibcode:1978ApJ...222..800K. doi:10.1086/156199.
  6. ↑ Rojas, Sebastián García. "Galaxy NGC 7013 · Deep Sky Objects Browser". DSO Browser. Retrieved 2017-05-18.
  7. ↑ "New General Catalog Objects: NGC 7000 – 7049". cseligman.com. Retrieved 2017-04-15.
  8. ↑ V. L. Afanasiev, O. K. Sil’chenko (13 December 2001). "Chemically distinct nuclei and circumnuclear rings in lenticular galaxies NGC 4429 and NGC 7013" (PDF): 13.
  9. 1 2 Normandin, George P. "NGC 7013, Spiral Galaxy". www.kopernik.org. Retrieved 2017-05-21.
  10. ↑ "Your NED Search Results". ned.ipac.caltech.edu. Retrieved 2017-09-03.
  11. ↑ Prieto, M.; Aguerri, J. A. L.; Varela, A. M.; Muñoz-Tuñón, C. (15 February 2001). "Optical surface photometry of a sample of disk galaxies". Astronomy & Astrophysics. 367 (2): 405–427. arXiv:astro-ph/0012110. Bibcode:2001A&A...367..405P. doi:10.1051/0004-6361:20000426.
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