Gamma-ray Flaring Emission in Blazar OJ287 Located in the Jet >14 pc from the Black Hole

I. Agudo; S. G. Jorstad; A. P. Marscher; V. M. Larionov; J. L. Gomez; A. Lahteenmaki; M. A. Gurwell; P. S. Smith; H. Wiesemeyer; C. Thum; J. Heidt

arXiv · 1110.6463

Gamma-ray Flaring Emission in Blazar OJ287 Located in the Jet >14 pc from the Black Hole

I. Agudo·S. G. Jorstad·A. P. Marscher·V. M. Larionov·J. L. Gomez·A. Lahteenmaki·M. A. Gurwell·P. S. Smith·H. Wiesemeyer·C. Thum·J. Heidt

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Abstract

We combine the Fermi-LAT light curve of the BL Lacertae type blazar OJ287 with time-dependent multi-waveband flux and linear polarization observations and submilliarcsecond-scale polarimetric images at lambda=7mm to locate the gamma-ray emission in prominent flares in the jet of the source >14pc from the central engine. We demonstrate a highly significant correlation between the strongest gamma-ray and millimeter-wave flares through Monte Carlo simulations. The two reported gamma-ray peaks occurred near the beginning of two major millimeter-wave outbursts, each of which is associated with a linear polarization maximum at millimeter wavelengths. Our very long baseline array observations indicate that the two millimeter-wave flares originated in the second of two features in the jet that are separated by >14pc. The simultaneity of the peak of the higher-amplitude gamma-ray flare and the maximum in polarization of the second jet feature implies that the gamma-ray and millimeter-wave flares are cospatial and occur >14pc from the central engine. We also associate two optical flares, accompanied by sharp polarization peaks, with the two gamma-ray events. The multi-waveband behavior is most easily explained if the gamma-rays arise from synchrotron self Compton scattering of optical photons from the flares. We propose that flares are triggered by interaction of moving plasma blobs with a standing shock.

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I. Agudo, S. G. Jorstad, A. P. Marscher, V. M. Larionov, J. L. Gomez, A. Lahteenmaki, M. A. Gurwell, P. S. Smith, H. Wiesemeyer, C. Thum, J. Heidt. 2011-10-28. Gamma-ray Flaring Emission in Blazar OJ287 Located in the Jet >14 pc from the Black Hole. https://arxiv.org/abs/1110.6463

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