NGC 4559

NGC 4559 (also known as Caldwell 36) is an intermediate spiral galaxy with a weak inner ring structure in the constellation Coma Berenices. Its velocity with respect to the cosmic microwave background is 1,096±20 km/s, which corresponds to a Hubble distance of 52.7 ± 3.8 Mly (16.17 ± 1.17 Mpc).^[1] However, 26 non-redshift measurements give a much closer distance of 24.56 ± 1.58 Mly (7.530 ± 0.483 Mpc).^[2] It was discovered by German-British astronomer William Herschel on 11 April 1785.^[3][4]

NGC 4559
NGC 4559 imaged by the Sloan Digital Sky Survey
Observation data (J2000 epoch)
Constellation	Coma Berenices
Right ascension	12h 35m 57.6285s[1]
Declination	+27° 57′ 35.851″[1]
Redshift	0.002715±0.000002[1]
Heliocentric radial velocity	814 ± 1 km/s[1]
Distance	24.56 ± 1.58 Mly (7.530 ± 0.483 Mpc)[1]
Apparent magnitude (V)	10.4[1]
Characteristics
Type	SAB(rs)cd[1]
Size	~92,900 ly (28.48 kpc) (estimated)[1]
Apparent size (V)	10.7′ × 4.4′[1]
Other designations
HOLM 423A, IRAS 12334+2814, UGC 7766, MCG +05-30-030, PGC 42002, CGCG 159-024, C 36[1]

NGC 4559 is a member of the Coma I Group.^[5][6]

Supernova

One supernova has been recorded in NGC 4559: SN 1941A (Type II-L, mag. 13.2)^[7] was discovered by Rebecca Jones on 24 February 1941, and after checking previous photographs of the galaxy, it was determined that the supernova was visible starting 5 February 1941.^[8]

Luminous Blue Variable

NGC 4559 is home to the luminous blue variable AT 2016blu (also known as PSN J12355230+2755559, or as NGC 4559OT). It was discovered by the Lick Observatory Supernova Search (LOSS) on 11 January 2012.^[9][10] It experiences repeated supernova-like outbursts: first when discovered, then again in 2014, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2024, and 2025.^[11][12]

See also

• Messier 99 – a similar spiral galaxy
• List of NGC objects (4001–5000)

Gallery

• 
  Hubble Space Telescope showing the inner structure
• 
  Hubble image of IC 3550, located in NGC 4559.