NGC 4051 is an intermediate spiral galaxy at a distance of 54 million light-years in the constellation of Ursa Major. NGC 4051 contains a supermassive black hole with a mass of 1.73 million M☉. 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.
