NGC 4045
NGC4045 is a barred spiral galaxy in the constellation of Virgo. Its velocity with respect to the cosmic microwave background is, which corresponds to a Hubble distance of. However, 15 non-redshift measurements give a closer mean distance of. It was discovered by German-British astronomer William Herschel on 20 December 1784. It was also observed by German astronomer Heinrich Louis d'Arrest on 10 April 1863, causing it to be listed a second time in the New General Catalogue, as NGC 4046.
NGC4045 is a LINER galaxy, i.e. a galaxy whose nucleus has an emission spectrum characterized by broad lines of weakly ionized atoms. Also, the galaxy is listed as having an active galactic nucleus, and as being a radio galaxy.
NGC4045 and neighboring galaxy PGC38033 are listed together as Holm320 in Erik Holmberg's A Study of Double and Multiple Galaxies Together with Inquiries into some General Metagalactic Problems, published in 1937. However, since PGC 38033 is over twice as distant as NGC 4045, the grouping is purely an optical alignment.
Supernova and luminous blue variable
One supernova has been observed in NGC 4045:SN1985B was discovered by Shingo Horiguchi on 17 January 1985. A 1987 study classified this supernova as TypeIa.One luminous blue variable has been observed in NGC 4045:AT2019wbg was discovered by Asteroid Terrestrial-impact [Last Alert System|ATLAS] on 3 December 2019. It was initially classified as a supernova impostor, then as a TypeIIn supernova. In June 2020 it was finally classified as a luminous blue variable, due to its continued up-and-down variability and low luminosity. Since then, it has exhibited repeated outbursts which have confirmed this classification.