Observational Implications of OJ 287's Predicted 2022 Disk Impact in the Black Hole Binary Model

TL;DR

This paper reports on the 2021/2022 observational campaign of OJ 287, confirming key predictions of the binary black hole model through observed flares and jet activity, providing new insights into the system's dynamics.

Contribution

It provides the first direct observational evidence of the secondary black hole in OJ 287 and confirms the orbit model through flare timing and properties.

Findings

Detection of a blue flash similar to 2005 during 2022 impact

Identification of a flare at the disk crossing confirming the orbit model

Observation of a one-day flare likely from secondary black hole jet lighting

Abstract

We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is special in the binary model because the major axis of the precessing binary happens to lie almost exactly in the plane of the accretion disc of the primary. This leads to pairs of almost identical impacts between the secondary black hole and the accretion disk in 2005 and 2022. In 2005, a special flare called "blue flash" was observed 35 days after the disk impact, which should have also been verifiable in 2022. We did observe a similar flash and were able to obtain more details of its properties. We describe this in the framework of expanding cloud models. In addition, we were able to identify the flare arising exactly at the time of the disc crossing from its photo-polarimetric and gamma-ray properties. This is an important identification, as it directly confirms the orbit model. Moreover, we saw a huge flare that lasted only one day. We may understand this as the lighting up of the jet of the secondary black hole when its Roche lobe is suddenly flooded by the gas from the primary disk. Therefore, this may be the first time we directly observed the secondary black hole in the OJ 287 binary system.