Blazars are active galactic nuclei with strong jets. They
tend to exhibit dramatic and unpredictable flux variations, namely outbursts.
Certain observed outbursts from an exceptional Blazar OJ287
can be explained by invoking a massive black hole binary as its central engine.
Detailed General Relativistic modeling allowed us to predict a major
optical outburst during November 2015.
The outburst did occur within the expected time range, peaking on 5/12/2015.
A multi-wavelength observational campaign confirmed the occurrence of certain
impact flare and the presence of a major thermal component in the flare, as predicted.
These observations and subsequent analysis allowed us to establish
the possible presence of
a spinning supermassive black hole binary that spirals in due to the emission of
nano-Hertz gravitational waves in the central engine of OJ287.
I will briefly list our on-going efforts that should be interesting to
the Event Horizon Telescope Consortium and the International Pulsar Timing Array.
