NGC 4151

NGC 4151 is a barred spiral galaxy of type SBab and lies in the constellation Canes Venatici. The galaxy has an angular extent of 6.3 '× 4.5 ' and an apparent magnitude of 10.3 mag and was discovered on March 17, 1787 by William Herschel. The distance from the Earth is 43 million light years. In the center of the galaxy there is a supermassive black hole, which emits X-rays. The exact origin of this radiation is unknown as yet (as of March 2011).