Abstract

The compact binary system in OJ287 is modelled to contain a spinning primary black hole with an accretion disk and a non-spinning secondary black hole. Using Post Newtonian (PN) accurate equations that include 2.5PN accurate non-spinning contributions,  the leading order general relativistic and classical spin-orbit terms, 
the orbit of the binary black hole in  OJ287 is calculated and as expected it depends on the  spin of the primary black hole.  Using the orbital solution, the specific times when the orbit of the secondary crosses the accretion disk of the primary are 
evaluated such that the record of observed outbursts from 1913 up to 2007 
is reproduced. The timings of the outbursts are quite sensitive to the spin value. 
In order to reproduce all the known outbursts, including a newly discovered one in 1957, 
the Kerr parameter of the primary has to be 0.28 +- 0.08. 
 The quadrupole-moment contributions to the equations of motion allow us to constrain 
the `no-hair' parameter to be 1.0+-0.3 where 0.3 is the one sigma error.
This supports the `black hole no-hair theorem' within the achievable precision.