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

Research output: Contribution to journalArticleScientificpeer-review


  • 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

Research units

  • Aryabhatta Research Institute of Observational Sciences
  • University of Turku
  • Nordic Optical Telescope
  • Czech Technical University Prague
  • Czech Academy of Sciences
  • Jagiellonian University
  • Pedagogical University of Cracow
  • University of Helsinki
  • Tata Institute of Fundamental Research
  • University of Zielona Gora
  • ASI Science Data Center
  • Istituto Nazionale di Fisica Nucleare
  • European Space Agency - ESA
  • Liverpool John Moores University
  • California Institute of Technology


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
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 10 Sep 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • accretion, accretion disks, black hole physics, BL Lacertae objects: individual (OJ 287), ACTIVE GALACTIC NUCLEI, VARIABILITY, VISCOSITY, QUASARS, OJ-287

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