NGC 3169

NGC 3169 is a spiral galaxy about 75 million light years[3] away in the constellation Sextans. It has the morphological classification SA(s)a pec,[5] which indicates this is a pure, unbarred spiral galaxy with tightly-wound arms and peculiar features.[6] There is an asymmetrical spiral arm and an extended halo around the galaxy.[7]

NGC 3169
NGC 3169, by HST (ACS/318 nm,658 nm)
Observation data (J2000 epoch)
ConstellationSextans
Right ascension 10h 14m 15.099s[1]
Declination+03° 27′ 58.03″[1]
Redshift+0.004113 ± 0.000017[2]
Helio radial velocity+1,232[3] km/s
Distance57 Mly (17.43 Mpc)[3]
Apparent magnitude (V)10.3
Characteristics
TypeSA(s)a pec[4]
Apparent size (V)4.2′ × 2.9′
Other designations
UGC 5525, PGC 29855[4]

This is a LINER 2 galaxy that displays an extended emission of X-rays in the region of the nucleus.[8] A hard X-ray source at the center most likely indicates an active galactic nucleus.[9] The stellar population in the nucleus, and a ring at an angular radius of 6″, shows an age of only one billion years and is generally younger than the surrounding stellar population. This suggests that a burst of star formation took place in the nucleus roughly one billion years ago.[5]

In 1984, a Type II-L supernova was discovered in this galaxy. Designated 1984E, the spectrum of this event at maximum light showed prominent balmer lines that indicated the explosion occurred inside a dense shell of hydrogen surrounding the star. This shell was likely created by a strong stellar wind from the progenitor star.[10] A second supernova was discovered in 2003; this time of type 1a. It was designated SN 2003 cg and reached peak magnitude 15.94.[11]

NGC 3169 is located in close physical proximity to NGC 3166, and the two have an estimated separation of around 160 kly (50 kpc). Their interaction is creating a gravitational distortion that has left the disk of NGC 3166 warped.[12] Combined with NGC 3156, the three galaxies form a small group within the larger Leo 1 group. The three are embedded within an extended ring of neutral hydrogen that is centered on NGC 3169.[5]

  • This image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile captures the pair of galaxies NGC 3169 (left) and NGC 3166 (right).
  • NGC 3169 image taken by Hubble.[13]

References
  1. 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.
  2. De Vaucouleurs, G.; De Vaucouleurs, A.; Corwin, Jr., H. G.; Buta, R. J.; Paturel, G.; Fouque, P. (1991), Third Reference Catalogue of Bright Galaxies, 3.9.CS1 maint: multiple names: authors list (link)
  3. Crook, Aidan C.; et al. (February 2007), "Groups of Galaxies in the Two Micron All Sky Redshift Survey", The Astrophysical Journal, 655 (2): 790–813, arXiv:astro-ph/0610732, Bibcode:2007ApJ...655..790C, doi:10.1086/510201.
  4. "NED results for object NGC 3169", NASA/IPAC Extragalactic Database, NASA, retrieved 2013-05-30.
  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, CiteSeerX 10.1.1.515.4412, doi:10.1134/S1063773706080044.
  6. Buta, Ronald J.; et al. (2007), Atlas of Galaxies, Cambridge University Press, pp. 13–17, ISBN 978-0521820486.
  7. Haynes, M. P. (August 1981), "Neutral hydrogen streams in groups of galaxies. I - Observations", Astronomical Journal, 86: 1126–1154, Bibcode:1981AJ.....86.1126H, doi:10.1086/112993.
  8. Terashima, Yuichi; Wilson, Andrew S. (January 2003), "Chandra Snapshot Observations of Low-Luminosity Active Galactic Nuclei with a Compact Radio Source", The Astrophysical Journal, 583 (1): 145–158, arXiv:astro-ph/0209607, Bibcode:2003ApJ...583..145T, doi:10.1086/345339.
  9. Mathur, Smita; et al. (October 2008), "AIP Conference Proceedings", American Institute of Physics Conference Series, 1053: 43–49, arXiv:0807.0422, Bibcode:2008AIPC.1053...43M, doi:10.1063/1.3009521.
  10. Henry, Richard B. C.; Branch, David (February 1987), "The spectrum of the type II-L supernova 1984E in NGC 3169 Further evidence for a superwind?", Publications of the Astronomical Society of the Pacific, 99: 112–115, Bibcode:1987PASP...99..112H, doi:10.1086/131962.
  11. Elias-Rosa, N.; et al. (July 2006), "Anomalous extinction behaviour towards the Type Ia SN 2003cg", Monthly Notices of the Royal Astronomical Society, 369 (4): 1880–1900, arXiv:astro-ph/0603316, Bibcode:2006MNRAS.369.1880E, doi:10.1111/j.1365-2966.2006.10430.x.
  12. Drory, Niv; Fisher, David B. (August 2007), "A Connection between Bulge Properties and the Bimodality of Galaxies", The Astrophysical Journal, 662 (2): 640–649, arXiv:0705.0973, Bibcode:2007ApJ...664..640D, doi:10.1086/519441.
  13. "Up and Over". www.spacetelescope.org. Retrieved 22 July 2019.


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