Markarian 231, seems to be the infant stage of Cygnus A quasar, both equipped with dual black holes !!

How?  According to Quantum FFF Theory, Black holes need a different NEW  physics theory , they repell fermions and produce  plasma Hydrogen around the double charged horizon etc. 

see: 

A different Black Hole Horizon Interpretation leading to Entropy Reduction and Violation of the Second Law.

http://vixra.org/pdf/1705.0153v4.pdf

However trhere is a large mass difference between the two BHs 150 million times the mass of the sun and the other 5 million times the mass of the sun.

According to Q/FFF Theory, this will not create a Cygnus A system with equal sized Bhs. The smaller BH should split the larger BH into two equal parts which could do the trick.
see below±

 Markarian 231.

.The great misconception in astronomy.