[4] Markarian 231 is located about 581 million light years away from Earth, in the constellation of Ursa Major.

A nuclear ring at the center has an active rate of star formation of greater than 100 solar masses per year.

It is one of the most ultraluminous infrared galaxies, with power derived from an accreting black hole in the center forming the closest known quasar.

X-ray data shows the energy released from the black hole produces ultra-fast outflows with a velocity of -20,000 km s−1.

[6] The Very Long Baseline Array found a triple radio source in Markarian 231.