NGC 3945
| NGC 3945 | |
|---|---|
 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]
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
[edit]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]
See also
[edit]References
[edit]- ^ a b 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.
- ^ a b c "NGC 3945". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-05-18.
- ^ a b c d e 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.
- ^ a b "Search specification: NGC 3945". HyperLeda. Université Claude Bernard Lyon 1. Retrieved 2021-05-18.
- ^ a b c "Results for object NGC 3945". NASA/IPAC Extragalactic Database. NASA and Caltech. Retrieved 26 May 2025.
- ^ Seligman, Courtney. "New General Catalogue objects: NGC 3900 - 3949". cseligman.com. Retrieved 2021-05-18.
- ^ 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.
- ^ 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.
- ^ 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.
External links
[edit]
Media related to NGC 3945 at Wikimedia Commons
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