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

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.

Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability

“…Here we are able to add seven more points (from Crimea) to the blue-flash light curve published in Valtonen et al (2023b) between JD 2,459,639 and JD 2,459,650. They confirm the maximum degree of polarization of ∼30% at JD 2,459,643, about a week later than the flux maximum calculated by van der Laan (1971) for a flare in 3C 273, with the scaling modified for the 2022 flare in OJ 287 by Valtonen et al (2023a).…”

“…The indirect aftereffects of the impact such as the lowpolarization flare were expected during July 2022 when OJ 287 was not observable by our instruments (Valtonen et al 2023a(Valtonen et al , 2023b. The entire data of the segment show PD and PA are correlated with R-band brightness.…”

“…Another exceptional finding is at the end of 2020 when both correlated and anticorrelated behaviors occur in the same flare. This is the time when in the binary model, the secondary jet was expected to show up and overpower the primary jet for a short period of time (Valtonen et al 2023a). This may be the first time (through polarization at least) that we actually see the emission of the secondary black hole in the binary black hole system of OJ 287.…”

“…From JD 2,459,575 (2021 December 26) to JD 2,459,735 (2022 June 4), the flux, PD, and PA follow the same variability trend and are correlated. This is the period when it has been argued (Valtonen et al 2023a) that the disk impact was detected from three different signals: a Roche lobe flare at JD 2,459,531, a gamma-ray flare at JD 2,459,600, and a blue flash at JD 2,459,635.…”

“…Within the extended binary SMBH scenario including a secondary BH jet, the gamma-ray flare should arise from the wind of the disk gas pressing on the secondary jet during the crossing of the secondary black hole through the primary disk (Araudo et al 2010). How this gamma-ray flare deviates from a typical blazar flare is discussed in Valtonen et al (2023a). In the optical, this flare shows up moderately in total flux but has a peculiar polarization behavior: the degree of polarization falls toward the flux peak, while the direction of polarization swings widely (Valtonen et al 2023b).…”