NGC 1566

NGC 1566
A close-up image of NGC 1566 taken by the Hubble’s Wide Field Camera 3.
Observation data (J2000 epoch)
ConstellationDorado
Right ascension04h 20m 00.40200s[1]
Declination−54° 56′ 16.5781″[1]
Redshift0.005017[2]
Heliocentric radial velocity1,506.1 km/s[3]
Distance69 Mly (21.3 Mpc)[4]
Apparent magnitude (V)9.73±0.03[5]
Characteristics
TypeSAB(rs)bc[4]
Mass6.5×1010[4] M☉
Apparent size (V)8′.51 × 5′.37[6]
Other designations
PGC 14897[2]

NGC 1566, sometimes known as the Spanish Dancer,[7][8][9] is an intermediate spiral galaxy in the constellation Dorado, positioned about 3.5° to the south of the star Gamma Doradus.[10] It was discovered on May 28, 1826 by Scottish astronomer James Dunlop.[11] At 10th magnitude,[5] it requires a telescope to view. The distance to this galaxy remains elusive, with measurements ranging from 6 Mpc[12] up to 21 Mpc.[4]

This galaxy forms a member of the NGC 1566 subgroup of the Dorado Group, of which it is dominant and brightest member[13][14][15] (although Kilborn and colleagues (2005) listed it as second brightest member of the NGC 1566 group after NGC 1553). The X-ray emission from the group is dominated by the hot gas halo of this galaxy, which extends out to 29 kpc before merging with the background radiation.[16] The galaxy appears to be interacting with smaller members of its subgroup.[12] Radio emissions suggest the disk is asymmetrical and the neutral hydrogen gas shows a mild warp.[4]

The morphological classification of NGC 1566 is SAB(rs)bc,[4] which indicates a spiral galaxy with a weak bar structure around the nucleus (SAB), an incomplete ring around the bar (rs), and showing wound arms (bc). The spiral arms are strong and symmetrical.[12] The galactic plane is inclined at an angle of 31°±7° to the line of sight to the Earth and the long axis is oriented along a position angle of 219°±4°.[4] The northwest side of the galaxy is more strongly obscured by dust, suggesting it is the near side.[12] The mass ratio of neutral hydrogen gas to the mass of the stars is 0.29, which is on the high side for a galaxy of this mass.[4] Absolute luminosity is 3.7×1010 L☉,[16] and is calculated to contain 1.4×1010 M☉ of H I.[16]

NGC 1566 is an active galaxy with many features of a Seyfert type 1, although the exact type remains uncertain. It is one of the closest and brightest Seyfert galaxies. The mass of the supermassive black hole at the center is estimated at (1.3±0.6)×107 M☉. The proximity of the galaxy, along with strong spiral arms and an active nucleus, have made it the subject of much scientific study in the astronomy community.[12] It is the nearest known CL AGN galaxy.[17]

On June 19, 2010, Berto Monard from South Africa detected a magnitude 16 supernova 13″ west and 22″ south of the center of NGC 1566.[18] It was designated SN 2010el[19] and was of type Iax.[20] A second supernova was discovered on 11 November 2021: SN 2021aefx (Type Ia, mag 12).[21]

Spanish Dancer Galaxy Twirls into View from NSF’s NOIRLab in Chile [22]
Image of NGC 1566 taken by James Webb's Mid-Infrared Instrument
  1. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference ned was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Meyer2004 was invoked but never defined (see the help page).
  4. ^ a b c d e f g h Cite error: The named reference Elagli2019 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Armando2007 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Paturel2003 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference billionsandbillions was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference photoshelter was invoked but never defined (see the help page).
  9. ^ Chadwick, Stephen; Cooper, Ian (11 December 2012). Imaging the Southern Sky. Springer. p. 260. ISBN 978-1461447498.
  10. ^ Cite error: The named reference Sinnott1997 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference seligman was invoked but never defined (see the help page).
  12. ^ a b c d e Cite error: The named reference Slater2019 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference deVaucouleurs1973 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Huchraetal1982 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Firthetal2006 was invoked but never defined (see the help page).
  16. ^ a b c Cite error: The named reference Kilbornetal2005 was invoked but never defined (see the help page).
  17. ^ Xu, D. W.; Komossa, S.; Grupe, D.; Wang, J.; Xin, L. P.; Han, X. H.; Wei, J. Y.; Bai, J. Y.; Bon, E.; Cangemi, F.; Cordier, B.; Dennefeld, M.; Gallo, L. C.; Kollatschny, W.; Kong, De-Feng (2024). "Changing-Look Narrow-Line Seyfert 1 Galaxies, their Detection with SVOM, and the Case of NGC 1566". Universe. 10 (2): 61. arXiv:2401.10600. Bibcode:2024Univ...10...61X. doi:10.3390/universe10020061. ISSN 2218-1997.
  18. ^ Cite error: The named reference Monard2010 was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference supernovae.net was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference Takaro2020 was invoked but never defined (see the help page).
  21. ^ Transient Name Server entry for SN 2021aefx. Retrieved 4 January 2023.
  22. ^ Spanish Dancer Galaxy Twirls into View from NSF’s NOIRLab in Chile Retrieved 30 January 2023.