OJ287: Post-Newtonian Calculation in Harmonic Coordinate and Pulsar Timing Residual Confirmation* *Supported by National Natural Science Foundation of China under Grant Nos. 11275187, 11421303, and the Strategic Priority Research Program “The Emergence of Cosmological Structures” of the Chinese Academy of Sciences under Grant No. XDB09000000

Abstract

We calculate and discuss the motion of the binary black hole OJ287 based on Post-Newtonian approximation in a harmonic coordinate. With gravitational waveform obtained, theoretical timing residual of PSR B1855+09 induced by gravitational radiation of OJ287 is presented and compared with observed data, further shows that hypothesis referring to OJ287 as a binary BH system might be proper. The energy flux of gravitational radiation from binary is also provided, from which we find that the flux changes sign successively: ĖN > 0, Ė1PN < 0, Ė2PN > 0, in agreement with the relative signs of forces of each PN order, revealed in the previous work.