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arXiv · 2204.10244

MOMO V. Effelsberg, Swift and Fermi study of the blazar and supermassive binary black hole candidate OJ 287 in a period of high activity

S. Komossa·D. Grupe·A. Kraus·A. Gonzalez·L. C. Gallo·M. J. Valtonen·S. Laine·T. P. Krichbaum·M. A. Gurwell·J. L. Gomez·S. Ciprini·I. Myserlis·U. Bach
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Abstract

We report results from our ongoing project MOMO (Multiwavelength Observations and Modelling of OJ 287). In this latest publication of a sequence, we combine our Swift UVOT--XRT and Effelsberg radio data (2.6-44 GHz) between 2019 and 2022.04 with public SMA data and gamma-ray data from the Fermi satellite. The observational epoch covers OJ 287 in a high state of activity from radio to X-rays. The epoch also covers two major events predicted by the binary supermassive black hole (SMBH) model of OJ 287. Spectral and timing analyses clearly establish: a new UV-optical minimum state in 2021 December at an epoch where the secondary SMBH is predicted to cross the disk surrounding the primary SMBH; an overall low level of gamma-ray activity in comparison to pre-2017 epochs; the presence of a remarkable, long-lasting UV--optical flare event of intermediate amplitude in 2020--2021; a high level of activity in the radio band with multiple flares; and particularly a bright, ongoing radio flare peaking in 2021 November that may be associated with a gamma-ray flare, the strongest in 6 years. Several explanations for the UV--optical minimum state are explored, including the possibility that a secondary SMBH launches a temporary jet, but the observations are best explained by variability associated with the main jet.

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S. Komossa, D. Grupe, A. Kraus, A. Gonzalez, L. C. Gallo, M. J. Valtonen, S. Laine, T. P. Krichbaum, M. A. Gurwell, J. L. Gomez, S. Ciprini, I. Myserlis, U. Bach. 2022-04-21. MOMO V. Effelsberg, Swift and Fermi study of the blazar and supermassive binary black hole candidate OJ 287 in a period of high activity. https://doi.org/10.1093/mnras%2Fstac792

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