Blazars are highly variable extra galactic sources, often undergoing rapid and dramatic fluctuations in brightness and these outbursts are very difficult to predict. However, certain observed outbursts from an exceptional Blazar OJ 287 can be explained due to the presence of a massive black hole(BH) binary in its central region. Detailed General Relativistic modeling allowed us to predict major optical outbursts during September 2007, November 2015 and finally during 31, July 2019. Observational campaigns confirmed occurrences of secondary BH impact-induced flares from OJ 287 in these epochs. I will detail how these efforts allowed us to establish the presence of a supermassive black hole binary that emits nano-Hertz gravitational waves in OJ 287.Our on-going efforts, relevant to both the Event Horizon Telescope consortium and the International Pulsar Timing Array consortium will be listed.
i) https://www.bbc.com/news/science-environment-52464250
ii) https://www.youtube.com/watch?v=HBE8qBtQMuA
