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NGC 1947

NGC 1947
NGC 1947 by Hubble Space Telescope
Observation data (J2000 epoch)
ConstellationDorado
Right ascension05h 26m 47.6s[1]
Declination−63° 45′ 36″[1]
Redshift0.003669 ± 0.000080 [1]
Heliocentric radial velocity1,100 ± 24 km/s[1]
Distance47.8 ± 11.7 Mly (14.65 ± 3.6 Mpc)[1]
Apparent magnitude (V)10.8[2]
Characteristics
TypeS0- pec [1]
Apparent size (V)3.0′ × 2.6′[1]
Notable featuresPolar-ring
Other designations
ESO 085-G87, AM 0526-634, IRAS 05264-6347, PGC 17296[1]

NGC 1947 is a peculiar lenticular galaxy in the constellation Dorado. The galaxy lies about 50 million light years away from Earth, which means, given its apparent dimensions, that NGC 1947 is approximately 75,000 light years across.[1] It was discovered by James Dunlop on November 5, 1826.[3]

Characteristics

The galaxy is characterised by the presence of dust lanes across the minor axis of the galaxy, indicating it is a polar-ring galaxy.[4] The galaxy has one central dust lane while three more less pronounced lanes are visible which look like concentric rings. Although it is categorised as a lenticular galaxy, it lacks a disk, having thus more in common with elliptical galaxies.[5]

Molecular gas has been detected around the nucleus of the galaxy with an estimated hydrogren mass of 4.2×108 M☉.[6] The gas rotates in an axis perpendicular to that of the stars of the galaxy, but in its inner region it is warped. The kinematics suggest that the dust and gas have an external origin, probably accreted from a gas-rich galaxy, as there is a lack of tidal tails that would indicate it is as a result of an unequal mass merger with a disk galaxy.[4]

The nucleus of the galaxy has been found to be active and it is categorised as a LINER.[7] The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole.

Nearby galaxies

NGC 1947 is the brightest galaxy in the NGC 1947 group, which also includes the galaxies ESO 085–065, ESO 085–088, and ESO 086–010. This group lies close to the Dorado Group,[8] and is part of the Southern Supercluster.[9]

References

  1. ^ a b c d e f g h i "NASA/IPAC Extragalactic Database". Results for NGC 1947. Retrieved 2024-03-26.
  2. ^ "Revised NGC Data for NGC 1947". spider.seds.org. Retrieved 30 March 2024.
  3. ^ Seligman, Courtney. "NGC 1947 (= PGC 17296 = ESO 085-087)". Celestial Atlas. Retrieved 19 November 2018.
  4. ^ a b Spavone, M.; Iodice, E.; Calvi, R.; Bettoni, D.; Galletta, G.; Longo, G.; Mazzei, P.; Minervini, G. (11 February 2009). "Revisiting the formation history of the minor-axis dust lane galaxy NGC 1947". Monthly Notices of the Royal Astronomical Society. 393 (1): 317–328. arXiv:0811.1754. Bibcode:2009MNRAS.393..317S. doi:10.1111/j.1365-2966.2008.14231.x.
  5. ^ Bertola, F.; Galetta, G.; Zeilinger, W. W. (1 February 1992). "The minor-axis dust-lane elliptical NGC 1947". Astronomy and Astrophysics. 254: 89–92. Bibcode:1992A&A...254...89B. ISSN 0004-6361.
  6. ^ Sage, Leslie J.; Galletta, Giuseppe (December 1993). "Evolution in Dust Lane Ellipticals: Detection of Accreted Molecular Gas". The Astrophysical Journal. 419: 544. Bibcode:1993ApJ...419..544S. doi:10.1086/173507.
  7. ^ Ricci, T V; Steiner, J E; Menezes, R B; Slodkowski Clerici, K; da Silva, M D (21 April 2023). "The DIVING3D Survey – Deep IFS View of Nuclei of Galaxies – III. Analysis of the nuclear region of the early-type galaxies of the sample". Monthly Notices of the Royal Astronomical Society. 522 (2): 2207–2222. arXiv:2304.13899. doi:10.1093/mnras/stad1130.
  8. ^ Makarov, Dmitry; Karachentsev, Igor (21 April 2011). "Galaxy groups and clouds in the local (z~ 0.01) Universe". Monthly Notices of the Royal Astronomical Society. 412 (4): 2498–2520. arXiv:1011.6277. Bibcode:2011MNRAS.412.2498M. doi:10.1111/j.1365-2966.2010.18071.x. S2CID 119194025.
  9. ^ Fouque, P.; Gourgoulhon, E.; Chamaraux, P.; Paturel, G. (1992-05-01). "Groups of galaxies within 80 Mpc. II. The catalogue of groups and group members". Astronomy and Astrophysics Supplement Series. 93: 211–233. ISSN 0365-0138.
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