NGC 3166 is a lenticular galaxy in the constellation Sextans. The galaxy lies about 65 million light years away from Earth, which means, given its apparent dimensions, that NGC 3166 is approximately 105,000 light years across.[1] It was discovered by William Herschel on December 19, 1783.[3]

Characteristics

NGC 3166 has a bright, elongated nucleus, surrounded by an elliptical bright bulge, elongated along a nearly east-west axis.[4] In the central 6-7 arcseconds there are evidence of a circumnuclear star disk. The age of the stars in the nucleus is estimated to be no older than two billion years.[5] A low-surface-brightness bar is visible lying nearly perpendicular to that. The fainter parts of the bulge are nearly circular, about one arcminute in diameter, and with spiral whorls. Beyond that lies a low-sufrace-brightness disk, without spiral arms or knots.[4] Dust lanes are visible over the disk the galaxy.[6] The star in the disk have sub-solar metallicity, indicating the star are more than 8 billion years old there.[7]

In ultraviolet the galaxy is asymmetric, with stronger emission west of the nucleus. That region, at the western tidal arm, is the only in the galaxy that has spectrum similar to an HII region and is indicative of the presence of young stars. There is hydrogen emission east of the nucleus. These asymmetry could be the result of recent gas accretion, and a complete star formation ring hasn't yet formed.[8] The current star formation rate of the galaxy is estimated to be 0.06±0.01 M☉ per year.[9] An arm is visible in H-alpha 100 arcseconds west of the nucleus. The outer regions of the galaxy appear lopsided.[8]

Supernova

One supernova has been detected in NGC 3166, SN 2012cw. The supernova was discovered on 14 June 2012 by Koichi Itagaki at an apparent magnitude of 16.5. Its spectrum showed it was a type Ic supernova two days post maximum.[10] Its progenitor couldn't be detected in archive images by Hubble Space Telescope, indicating it had an absolute magnitude of less than -7.[11]

Nearby galaxies

NGC 3166 forms an interacting pair with NGC 3169, which lies at a separation of 7.5 arcminutes. Another companion galaxy, NGC 3165, lies 4.5 arcminutes to the southwest.[6] A tidal tail connecting NGC 3166 with NGC 3169 extending south of the galaxy is visible in radiowaves, in the hydrogen line. The total mass of hydrogen in the tail is estimated to be 108 M☉.[12] At the end of the tail a tidal dwarf galaxy, AGC 208457, has formed.[13] Some other gas clumps have also been detected. Three of them are classical dwarf irregular galaxies.[9] There is extended hydrogen emission surrounding the group.[12] These galaxies, along with NGC 3156, form the NGC 3169 Group, which is part of the Leo II Groups, a large cloud of galaxies in the Virgo Supercluster.[14]

References

  1. ^ a b c d e f g h "NASA/IPAC Extragalactic Database". Results for NGC 3166. Retrieved 12 February 2025.
  2. ^ "Revised NGC Data for NGC 3166". spider.seds.org. Retrieved 30 March 2024.
  3. ^ Seligman, Courtney. "NGC 3166 (= PGC 29814 = PGC 1251971)". Celestial Atlas. Retrieved 19 November 2018.
  4. ^ a b Eskridge, Paul B.; Frogel, Jay A.; Pogge, Richard W.; Quillen, Alice C.; Berlind, Andreas A.; Davies, Roger L.; DePoy, D. L.; Gilbert, Karoline M.; Houdashelt, Mark L.; Kuchinski, Leslie E.; Ramirez, Solange V.; Sellgren, K.; Stutz, Amelia; Terndrup, Donald M.; Tiede, Glenn P. (November 2002). "Near-Infrared and Optical Morphology of Spiral Galaxies". The Astrophysical Journal Supplement Series. 143 (1): 73–111. arXiv:astro-ph/0206320. Bibcode:2002ApJS..143...73E. doi:10.1086/342340.
  5. ^ Sil’chenko, O. K.; Afanasiev, V. L. (August 2006). "Central regions of the early-type galaxies in the NGC 3169 group". Astronomy Letters. 32 (8): 534–544. Bibcode:2006AstL...32..534S. doi:10.1134/S1063773706080044.
  6. ^ a b Sandage, A., Bedke, J. (1994), The Carnegie Atlas of Galaxies. Volume I, Carnegie Institution of Washington
  7. ^ Sil'chenko, O. K.; Proshina, I. S.; Shulga, A. P.; Koposov, S. E. (21 November 2012). "Ages and abundances in large-scale stellar discs of nearby S0 galaxies: Discs of S0 galaxies". Monthly Notices of the Royal Astronomical Society. 427 (1): 790–805. doi:10.1111/j.1365-2966.2012.21990.x.
  8. ^ a b Sil’chenko, Olga K.; Moiseev, Alexei V.; Egorov, Oleg V. (1 September 2019). "The Gas Kinematics, Excitation, and Chemistry, in Connection with Star Formation, in Lenticular Galaxies". The Astrophysical Journal Supplement Series. 244 (1): 6. arXiv:1907.07261. Bibcode:2019ApJS..244....6S. doi:10.3847/1538-4365/ab3415. ISSN 0067-0049.
  9. ^ a b Lee-Waddell, K.; Spekkens, K.; Chandra, P.; Patra, N.; Cuillandre, J.-C.; Wang, J.; Haynes, M. P.; Cannon, J.; Stierwalt, S.; Sick, J.; Giovanelli, R. (11 August 2016). "The frequency and properties of young tidal dwarf galaxies in nearby gas-rich groups". Monthly Notices of the Royal Astronomical Society. 460 (3): 2945–2961. doi:10.1093/mnras/stw1162.
  10. ^ Itagaki, K.; Noguchi, T.; Nakano, S.; Yusa, T.; Wang, X. -F.; Liu, Q.; Zhang, J. -J.; Zhang, T. -M. (19 June 2012). "Supernova 2012cw in NGC 3166 = Psn J10134795+0326026". Central Bureau Electronic Telegrams (3148): 1. Bibcode:2012CBET.3148....1I.
  11. ^ Graur, Or; Maoz, Dan (21 June 2012). "No progenitor detected to M_V ~ -7 mag for Type-Ic SN 2012cw". The Astronomer's Telegram. 4199: 1. Bibcode:2012ATel.4199....1G.
  12. ^ a b Lee-Waddell, K.; Spekkens, K.; Haynes, M. P.; Stierwalt, S.; Chengalur, J.; Chandra, P.; Giovanelli, R. (11 December 2012). "Pre-existing dwarfs, tidal knots and a tidal dwarf galaxy: an unbiased H i study of the gas-rich interacting galaxy group NGC 3166/9: An unbiased H i study of NGC 3166/9". Monthly Notices of the Royal Astronomical Society. 427 (3): 2314–2327. doi:10.1111/j.1365-2966.2012.22115.x.
  13. ^ Lee-Waddell, K; Madrid, J P; Spekkens, K; Donzelli, C J; Koribalski, B S; Serra, P; Cannon, J (21 October 2018). "Optical spectroscopy of young tidal objects around two interacting galaxy pairs". Monthly Notices of the Royal Astronomical Society. 480 (2): 2719–2725. doi:10.1093/mnras/sty2042.
  14. ^ "The Leo II Groups". www.atlasoftheuniverse.com. Retrieved 12 February 2025.
Allikas: https://en.wikipedia.org/wiki/NGC_3166
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