NGC 3945

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]

ConstellationUrsa Major

Right ascension11^h 53^m 13.726^s[1]

Declination+60° 40′ 32.02″^[1]

Redshift0.004153^[2]

Quick facts Observation data (J2000 epoch), Constellation ...

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]

Close

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]