The
morphological class of NGC 5584 is SAB(rs)cd,[8] which indicates this spiral galaxy has an inner bar (SAB), an incomplete inner ring structure (rs), and loosely wound
spiral arms (cd). It is
flocculent in appearance with only a small nucleus.
Star formation is occurring along the spiral arms.[8] The
galactic plane is inclined at an angle of 42.4° to the line of sight from the Earth,[7] and it spans more than 50,000 light-years across.[12] 250
Cepheid variables have been observed in NGC 5584.[1]
Two supernova events have been observed in NGC 5584. SN 1996aq was a
Type Ic supernova discovered August 17, 1996 by Masakatsu Aoki in Japan. It was offset by 15
″ west and 8″ south of the galactic center. It reached magnitude 14.7 on August 18.[13]SN 2007af was spotted at magnitude 15.4 on February 24, 2007 by K. Itagaki, also of Japan. This was a
Type Ia supernova at an offset 40″ west and 22″ of the galaxy center.[14] A
light echo of this event was observed about 1,000 days after its discovery.[15]
^Buta, Ronald J.; et al. (September 2019). "A comprehensive examination of the optical morphologies of 719 isolated galaxies in the AMIGA sample". Monthly Notices of the Royal Astronomical Society. 488 (2): 2175–2189.
arXiv:1906.11677.
Bibcode:
2019MNRAS.488.2175B.
doi:
10.1093/mnras/stz1780.
^Nakano, S.; et al. (August 1996). Green, D. W. E. (ed.). "Supernova 1996aq in NGC 5584". IAU Circular. 6454 (1): 1.
Bibcode:
1996IAUC.6454....1N.
^Hurst, G. M. (October 2007). "Supernova 2007af in NGC 5584". Journal of the British Astronomical Association. 117 (5): 280–281.
Bibcode:
2007JBAA..117..280H.
^Drozdov, Dina; Leising, M. D.; Milne, P.; Riess, A. G. (June 2013). "The Detection of a Light Echo from Type Ia SN 2007af in NGC 5584". American Astronomical Society, AAS Meeting #222. 222.
Bibcode:
2013AAS...22211804D. 118.04.