NGC 4051

NGC 4051 is an intermediate spiral galaxy in the constellation of Ursa Major. It was discovered on 6 February 1788 by William Herschel.
NGC 4051 contains a supermassive black hole with a mass of 1.73 million [Solar mass|]. This galaxy was studied by the Multicolor Active Galactic Nuclei Monitoring 2m telescope.
The galaxy is a Seyfert galaxy that emits bright X-rays. However, in early 1998 the X-ray emission ceased as observed by the Beppo-SAX satellite. X-ray emission had risen back to normal by August 1998.
NGC 4051 is a member of the Ursa Major Cluster. Its peculiar velocity is −490 ± 34 km/s, consistent with the rest of the cluster. It is a member of the NGC 4111 Group, which is part of the Ursa Major Cloud and is the second largest group in the cloud after the NGC 3992 Group.

Supernovae

Three supernovae have been discovered in NGC 4051:SN 1983I was discovered independently by J. Kielkopf et al, on 11 May 1983, and by Tsvetkov on 12 May 1983.SN 2003ie was discovered by Ron Arbour on 19 September 2003.SN 2010br was discovered by Vitali Nevski on 10 April 2010.