Markarian 421
Markarian 421 is a blazar located in the constellation Ursa Major. The object is an active galaxy and a BL Lacertae object, and is a strong source of gamma rays. It is about 397 million light-years to 434 million light-years from the Earth. It is one of the closest blazars to Earth, making it one of the brightest quasars in the night sky. It is suspected to have a supermassive black hole at its center due to its active nature. An early-type high inclination spiral galaxy is located 14 arc-seconds northeast of Markarian 421.
It was first determined to be a very high energy gamma ray emitter in 1992 by M. Punch at the Whipple Observatory, and an extremely rapid outburst in very-high-energy gamma rays was measured in 1996 by J. Gaidos at Whipple Observatory
Markarian 421 also had an outburst in 2001 and is monitored by the Whole Earth Blazar Telescope project.
Due to its brightness the object can also be viewed by amateurs in smaller telescopes.
