NGC 613

NGC 613

NGC 613 imaged from the Paranal Observatory in Chile.[1] The prominent star at upper left is HD 9693.[2]
Observation data (J2000 epoch)
Constellation Sculptor
Right ascension 01h 34m 18.235s[3]
Declination –29° 25 06.56[3]
Helio radial velocity +1,487[4]
Distance 67.5 Mly (20.7 Mpc)[5]
Apparent magnitude (V) 10.0[6]
Characteristics
Type SBbc(rs)[7]
Apparent size (V) 5′.2 × 2′.6[6]

NGC 613 is a barred spiral galaxy located some 67[5] million light years away in the southern constellation of Sculptor.[8] It is a candidate outlying member of the Sculptor Group, a gravitationally-bound group of galaxies.[6] This galaxy was discovered in 1798 by German-English astronomer William Herschel, then re-discovered and catalogued by Scottish astronomer James Dunlop. It was first photographed in 1912, which revealed the spiral form of the nebula.[6] During the twentieth century, radio telescope observations showed that a linear feature in the nucleus was a relatively strong source of radio emission.[9]

NGC 613 is inclined by an angle of 37° to the line of sight from the Earth along a position angle of 125°.[10] The morphological classification of NGC 613 is SBbc(rs),[7] indicating that it is a spiral galaxy with a bar across the nucleus (SB), a weak inner ring structure circling the bar (rs), and moderate to loosely wound spiral arms (bc).[11] The bar is relatively broad but irregular in profile with a position angle that varies from 115–124° and dust lanes located along the leading edges. Star formation is occurring at the ends of the bar and extending along the well-defined spiral arms. The central bulge is readily apparent, with a radius of 14″.[10]

The classification of the nucleus is of type HII, indicating a match to the spectrum of an H II region. Near the core, the stars have a velocity dispersion of 136 ± 20 km/s. The nucleus is a source of radio emission with the form of an inner ring with a radius of about 1,100 ly (350 pc) and a linear feature that is perhaps perpendicular to it. The latter consists of three discrete blobs spanning approximately 2,000 ly (600 pc).[12] Observations suggest the presence of a supermassive black hole at the core with a mass in the range (1.9–9.6) × 107 times the mass of the Sun.[7]

References

  1. Nemiroff, R.; Bonnell, J., eds. (February 13, 2004). "NGC 613: Spiral of Dust and Stars". Astronomy Picture of the Day. NASA. Retrieved 2013-07-07.
  2. "HD 9693 -- Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2013-07-07.
  3. 1 2 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.
  4. da Costa, L. Nicolaci; et al. (July 1998), "The Southern Sky Redshift Survey", Astrophysical Journal, 116 (1): 1–7, arXiv:astro-ph/9804064Freely accessible, Bibcode:1998AJ....116....1D, doi:10.1086/300410.
  5. 1 2 Meurer, Gerhardt R.; et al. (July 2006), "The Survey for Ionization in Neutral Gas Galaxies. I. Description and Initial Results", The Astrophysical Journal Supplement Series, 165 (1): 307–337, arXiv:astro-ph/0604444Freely accessible, Bibcode:2006ApJS..165..307M, doi:10.1086/504685.
  6. 1 2 3 4 O'Meara, Stephen James (2013), Deep-Sky Companions: Southern Gems, Cambridge University Press, pp. 36–43, ISBN 1107015014.
  7. 1 2 3 Beifiori, A.; et al. (February 2009), "Upper Limits on the Masses of 105 Supermassive Black Holes from Hubble Space Telescope/Space Telescope Imaging Spectrograph Archival Data", The Astrophysical Journal, 692 (1): 856–868, arXiv:0809.5103Freely accessible, Bibcode:2009ApJ...692..856B, doi:10.1088/0004-637X/692/1/856.
  8. West, Richard (December 19, 2003), Three Dusty Beauties, European Southern Observatory, retrieved 2013-07-07.
  9. Hummel, E.; et al. (January 1987), "The central region of NGC 613. Evidence for an accelerated collimated outflow", Astronomy and Astrophysics, 172 (1–2): 51–54, Bibcode:1987A&A...172...51H.
  10. 1 2 Baumgart, C. W.; Peterson, C. J. (January 1986), "Near-infrared surface photometry of barred spiral galaxies", Publications of the Astronomical Society of the Pacific, 98: 56–69, Bibcode:1986PASP...98...56B, doi:10.1086/131721.
  11. Buta, Ronald J.; et al. (2007), Atlas of Galaxies, Cambridge University Press, pp. 13–17, ISBN 0521820480.
  12. Hummel, E.; Jorsater, S. (July 1992), "The central region of NGC 613 revisited", Astronomy and Astrophysics, 261 (1): 85–93, Bibcode:1992A&A...261...85H.
  13. "A spiral galaxy's brights and darks". Retrieved 1 October 2015.
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Coordinates: 01h 34m 18.235s, −29° 25′ 06.56″

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