NGC 3945 is a barred lenticular galaxy in the constellation Ursa Major. It was discovered on March 19, 1790, by the astronomer William Herschel.[5]
| NGC 3945 | |
|---|---|
 Hubble Space Telescope image of NGC 3945 | |
| 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] |
| Apparent magnitude (V) | 10.75[4] |
| Apparent magnitude (B) | 11.70[4] |
| Characteristics | |
| Type | (R)SB(rs)0+[3] |
| Other designations | |
| UGC 6860, MCG +10-17-096, PGC 37258[2] | |
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.[6] 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.[7]
References
External links
Media related to NGC 3945 at Wikimedia Commons