A1 Refereed original research article in a scientific journal
Refining the OJ 287 2022 impact flare arrival epoch
Authors: Valtonen Mauri J, Zola Staszek, Gopakumar A, Lähteenmäki Anne, Tornikoski Merja, Dey Lankeswar, Gupta Alok C, Pursimo Tapio, Knudstrup Emil, Gomez Jose L, Hudec Rene, Jelínek Martin, Štrobl Jan, Berdyugin Andrei V, Ciprini Stefano, Reichart Daniel E, Kouprianov Vladimir V, Matsumoto Katsura, Drozdz Marek, Mugrauer Markus, Sadun Alberto, Zejmo Michal, Sillanpää Aimo, Lehto Harry J, Nilsson Kari, Imazawa Ryo, Uemura Makoto
Publisher: Oxford Univ Press
Publication year: 2023
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 521
Issue: 4
First page : 6143
Last page: 6155
Number of pages: 13
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/stad922
Web address : https://doi.org/10.1093/mnras/stad922
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/179824764
The bright blazar OJ 287 routinely parades high brightness bremsstrahlung flares, which are explained as being a result of a secondary supermassive black hole (SMBH) impacting the accretion disc of a more massive primary SMBH in a binary system. The accretion disc is not rigid but rather bends in a calculable way due to the tidal influence of the secondary. Next, we refer to this phenomenon as a variable disc level. We begin by showing that these flares occur at times predicted by a simple analytical formula, based on general relativity inspired modified Kepler equation, which explains impact flares since 1888. The 2022 impact flare, namely flare number 26, is rather peculiar as it breaks the typical pattern of two impact flares per 12-yr cycle. This is the third bremsstrahlung flare of the current cycle that follows the already observed 2015 and 2019 impact flares from OJ 287. It turns out that the arrival epoch of flare number 26 is sensitive to the level of primary SMBH's accretion disc relative to its mean level in our model. We incorporate these tidally induced changes in the level of the accretion disc to infer that the thermal flare should have occurred during 2022 July-August, when it was not possible to observe it from the Earth. Thereafter, we explore possible observational evidence for certain pre-flare activity by employing spectral and polarimetric data from our campaigns in 2004/05 and 2021/22. We point out theoretical and observational implications of two observed mini-flares during 2022 January-February.
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