Bright, extended ellipse; a bright nuclear structure is noticeably elongated; two weak spiral enhancements emerge from opposite sides of the nucleus, one curving towards a bright star attached on the south end. The galaxy is likely interacting with NGC 9.
One supernova has been observed in NGC 23. SN 1955C (type unknown, mag. 16) was discovered by Allan Sandage in September 1958 using the Hale Telescope. On a photographic plate taken 23 October 1955 (three years prior), a bright star with a visual magnitude around 16 was located 10″ to the north and 10″ east of the galactic center. The star was not visible on a photograph taken 60 days prior.[8][9]
References
^ abSkrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W.; Chester, Thomas; Elias, Jonathan H.; Huchra, John P.; Liebert, James W.; Lonsdale, Carol J.; Monet, David G.; Price, Stephan; Seitzer, Patrick; Jarrett, Thomas H.; Kirkpatrick, J. Davy; Gizis, John E.; Howard, Elizabeth V.; Evans, Tracey E.; Fowler, John W.; Fullmer, Linda; Hurt, Robert L.; Light, Robert M.; Kopan, Eugene L.; Marsh, Kenneth A.; McCallon, Howard L.; Tam, Robert; Van Dyk, Schuyler D.; Wheelock, Sherry L. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi:10.1086/498708. ISSN0004-6256. S2CID18913331.
^ abGarcía-Lorenzo, B.; et al. (January 2015). "Ionized gas kinematics of galaxies in the CALIFA survey. I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems". Astronomy & Astrophysics. 573: 43. arXiv:1408.5765. Bibcode:2015A&A...573A..59G. doi:10.1051/0004-6361/201423485. S2CID55475658. A59.