NGC 3977

NGC 3977
NGC 3977 imaged by SDSS
Observation data (J2000 epoch)
Constellation	Ursa Major
Right ascension	11h 56m 07.1952s[1]
Declination	+55° 23′ 26.718″[1]
Redshift	0.019370[1]
Heliocentric radial velocity	5,807±5 km/s[1]
Distance	287.4 ± 20.1 Mly (88.13 ± 6.17 Mpc)[1]
Group or cluster	Holm 304
Apparent magnitude (V)	13.4[1]
Characteristics
Type	(R)SA(rs)ab?[1]
Size	~156,600 ly (48.00 kpc) (estimated)[1]
Apparent size (V)	1.5′ × 1.4′[1]
Other designations
HOLM 304B, NGC 3980, UGC 6909, MCG +09-20-034, PGC 37497, CGCG 269-017[1]

NGC 3977 is an unbarred spiral galaxy in the constellation of Ursa Major. Its velocity with respect to the cosmic microwave background is 5,975±13 km/s, which corresponds to a Hubble distance of 287.4 ± 20.1 Mly (88.13 ± 6.17 Mpc).^[1] It was discovered by German-British astronomer William Herschel on 13 April 1784.^[2] It was also observed by Lewis Swift on 16 April 1885, causing this galaxy to be listed twice in the New General Catalogue, as both NGC 3977 and NGC 3980.^[2]

NGC 3977 along with NGC 3972 are listed together as Holm 304 in Erik Holmberg's A Study of Double and Multiple Galaxies Together with Inquiries into some General Metagalactic Problems, published in 1937.^[3] This grouping is purely optical, as NGC 3977 is about four times farther away than NGC 3972.^[4]

The SIMBAD database lists NGC 3977 as a LINER galaxy, i.e. a galaxy whose nucleus has an emission spectrum characterized by broad lines of weakly ionized atoms.^[5]

Two supernovae have been observed in NGC 3977:

• SN 1946A (type unknown, mag. 18) was discovered by Edwin Hubble in May 1946.^[6]
• SN 2006gs (type II, mag. 17.0) was discovered by Kōichi Itagaki on 22 September 2006.^[7][8]

• List of NGC objects (3001–4000)

• Media related to NGC 3977 at Wikimedia Commons
• NGC 3977 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images