Accretion Disk Parameters Determined from the Great 2015 Flare of OJ 287

Mauri J. Valtonen*, Staszek Zola, Pauli Pihajoki, Sissi Enestam, Harry J. Lehto, Lankeswar Dey, Achamveedu Gopakumar, Marek Drozdz, Waldemar Ogloza, Michal Zejmos, Alok C. Gupta, Tapio Pursimo, Stefano Ciprini, Mark Kidger, Kari Nilsson, Andrei Berdyugin, Vilppu Piirola, Helen Jermak, Rene Hudec, Seppo Laine

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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In the binary black hole model of OJ. 287, the secondary black hole orbits a much more massive primary, and impacts on the primary accretion disk at predictable times. We update the parameters of the disk, the viscosity, alpha, and the mass accretion rate, . We find alpha = 0.26 +/- 0.1 and = 0.08 +/- 0.04 in Eddington units. The former value is consistent with Coroniti, and the latter with Marscher & Jorstad. Predictions are made for the 2019 July 30 superflare in OJ. 287. We expect that it will take place simultaneously at the Spitzer infrared channels, as well as in the optical, and that therefore the timing of the flare in optical can be accurately determined from Spitzer observations. We also discuss in detail the light curve of the 2015 flare, and find that the radiating volume has regions where bremsstrahlung dominates, as well as regions that radiate primarily in synchrotron radiation. The former region produces the unpolarized first flare, while the latter region gives rise to a highly polarized second flare.

Original languageEnglish
Article number88
Number of pages8
JournalThe Astrophysical Journal
Issue number2
Publication statusPublished - 10 Sept 2019
MoE publication typeA1 Journal article-refereed


  • accretion
  • accretion disks
  • black hole physics
  • BL Lacertae objects: individual (OJ 287)
  • OJ-287


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