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)
ConstellationSculptor
Right ascension01h 34m 18.235s[3]
Declination–29° 25′ 06.56″[3]
Heliocentric radial velocity+1,487[4]
Distance67.5 Mly (20.7 Mpc)[5]
Apparent magnitude (V)10.0[6]
Characteristics
TypeSBbc(rs)[7]
Apparent size (V)5′.2 × 2′.6[6]
Other designations
MCG -05-04-044, PGC 5849[8]

NGC 613 is a barred spiral galaxy located 67 million light years away in the southern constellation of Sculptor.[5][9] 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.[10]

Hubble image of NGC 613 showing the prominent bar and loosely wound arms[11]

NGC 613 is inclined by an angle of 37° to the line of sight from the Earth along a position angle of 125°.[12] 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).[13] 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″.[12]

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).[14] 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]

  1. ^ Cite error: The named reference APoD_20040213 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference SIMBAD_HD_9693 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference ApJ131_1163 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference ApJ116_1_1 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference SpJSS165_1_307 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference OMeara2013 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference ApJ692_1_856 was invoked but never defined (see the help page).
  8. ^ "NGC 613". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-22.
  9. ^ Cite error: The named reference ESO2003dec19 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference AAA172_1_51 was invoked but never defined (see the help page).
  11. ^ "Sculpted in Sculptor". esahubble.org/. Retrieved 29 January 2021.
  12. ^ a b Cite error: The named reference PASP98_56 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Buta2007 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference AAA261_1_85 was invoked but never defined (see the help page).