Markarian 421

Markarian 421 ( Mrk 421, and Mkn 421 ) is a blazar in the constellation Ursa Major, which was systematically observed for the first time by Benjamin Markarian. He is about 500 million light -years away from Earth. In its center is a black hole, the resulting jet beam has nearly the speed of light is directed towards the Earth.

Markarian 421 has been observed since 1995 systematically with HEGRA in La Palma. Beginning of 2001, the previous highest activity was recorded.

Markarian 421 is one of Markarian 501 to the next and most high-energy gamma-ray sources. Both are important objects for testing new theoretical physical approaches.