NGC 3945

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NGC 3945
NGC 3945 lenticular Galaxy 13024680373 e2ca77db8d o.png
NGC 3945 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Constellation Ursa Major
Right ascension 11h 53m 13.726s [1]
Declination +60° 40′ 32.02″ [1]
Redshift 0.004153 [2]
Heliocentric radial velocity 1242 ± 22 km/s [2]
Distance 63  Mly (19.4  Mpc) [3]
Group or cluster NGC 4036 Group (LGG 266)
Apparent magnitude  (V)10.75 [4]
Apparent magnitude  (B)11.70 [4]
Characteristics
Type (R)SB(rs)0+ [3]
Size~128,800  ly (39.48  kpc) (estimated) [5]
Apparent size  (V)5.2′ × 3.5′ [5]
Other designations
IRAS 11506+6056, UGC 6860, MCG +10-17-096, PGC 37258, CGCG 292-042 [2] [5]

NGC 3945 is a barred lenticular galaxy in the constellation Ursa Major. It was discovered by German-British astronomer William Herschel on March 19, 1790. [6]

Contents

NGC 3945 has a complex structure, with two concentric bars and a pseudobulge. [3] Unlike classical bulges which are like miniature elliptical galaxies, pseudobulges have features similar to disk galaxies, including a flattened structure and significant rotation. [7] It is classified as a LINER galaxy. [3] The formation history of NGC 3945 is likely quite complex, with the pseudo-bulge being formed gradually from disk material, while bulges (spheroidal components) would have formed from violent merger events. [3]

Unlike galaxies with similar velocity dispersions and luminosities, the central black hole of NGC 3945 has an unusually low mass, estimated to be around 9×106  M☉. However, it is also possible that NGC 3945 has no central black hole at all. [8]

NGC 4036 Group

NGC 3945 is a part of the 13 member NGC 4036 galaxy group (also known as LGG 266), which includes NGC 4036, NGC 4041, IC 758, UGC 7009, UGC 7019, PGC 37567, PGC 38027, PGC 2608163, PGC 4001456, PGC 4001735, PGC 4011191, and PGC 4074702. [9]

The NGC 4036 Group is part of the Ursa Major Cloud, which is part of the Virgo Supercluster. [10]

See also

References

  1. 1 2 Skrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W.; Chester, Thomas; Elias, Jonathan H.; Huchra, John P.; Liebert, James W.; Lonsdale, Carol J.; Monet, David G.; Price, Stephan; Seitzer, Patrick; Jarrett, Thomas H.; Kirkpatrick, J. Davy; Gizis, John E.; Howard, Elizabeth V.; Evans, Tracey E.; Fowler, John W.; Fullmer, Linda; Hurt, Robert L.; Light, Robert M.; Kopan, Eugene L.; Marsh, Kenneth A.; McCallon, Howard L.; Tam, Robert; Van Dyk, Schuyler D.; Wheelock, Sherry L. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi: 10.1086/498708 . ISSN   0004-6256. S2CID   18913331.
  2. 1 2 3 "NGC 3945". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2021-05-18.
  3. 1 2 3 4 5 Dullo, Bililign T.; Martínez-Lombilla, Cristina; Knapen, Johan H. (2016). "Complex central structures suggest complex evolutionary paths for barred S0 galaxies". Monthly Notices of the Royal Astronomical Society. 462 (4): 3800–3811. arXiv: 1608.03539 . doi: 10.1093/mnras/stw1868 .
  4. 1 2 "Search specification: NGC 3945". HyperLeda. Université Claude Bernard Lyon 1. Retrieved 2021-05-18.
  5. 1 2 3 "Results for object NGC 3945". NASA/IPAC Extragalactic Database. NASA and Caltech . Retrieved 26 May 2025.
  6. ↑ Seligman, Courtney. "New General Catalogue objects: NGC 3900 - 3949". cseligman.com. Retrieved 2021-05-18.
  7. ↑ Fisher, David B.; Drory, Niv (2008). "The Structure of Classical Bulges and Pseudobulges: The Link Between Pseudobulges and Sérsic Index". The Astronomical Journal. 136 (2): 773–839. arXiv: 0805.4206 . Bibcode:2008AJ....136..773F. doi:10.1088/0004-6256/136/2/773. S2CID   16126374.
  8. ↑ Gültekin, Kayhan; Richstone, Douglas O.; Gebhardt, Karl; Lauer, Tod R.; Pinkney, Jason; Aller, M. C.; Bender, Ralf; Dressler, Alan; Faber, S. M.; Filippenko, Alexei V.; Green, Richard; Ho, Luis C.; Kormendy, John; Siopis, Christos (2009). "A Quintet of Black Hole Mass Determinations". The Astrophysical Journal. 695 (2): 1577–1590. arXiv: 0901.4162 . Bibcode:2009ApJ...695.1577G. doi:10.1088/0004-637X/695/2/1577. S2CID   14365610.
  9. ↑ Kourkchi, Ehsan; Tully, R. Brent (2017). "Galaxy Groups within 3500 km s-1". The Astrophysical Journal. 843 (1): 16. arXiv: 1705.08068 . Bibcode:2017ApJ...843...16K. doi: 10.3847/1538-4357/aa76db .
  10. ↑ Tully, R. Brent (1988). Nearby galaxies catalog (1. publ ed.). Cambridge: Cambridge University Press. ISBN   978-0-521-35299-4.

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