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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A Multi-Wavelength View of OJ 287 Activity in 2015-2017: Implications of Spectral Changes on Central-Engine Models and MeV-GeV Emission Mechanism

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Kushwaha, Pankaj
Total Authors: 1
Document type: Journal article
Source: GALAXIES; v. 8, n. 1 MAR 2020.
Web of Science Citations: 0

A diverse range of observational results and peculiar properties across the domains of observation have made OJ 287 one of the best-explored BL Lac objects on the issues of relativistic jets and accretion physics as well as the strong theory of gravity. We here present a brief compilation of observational results from the literature and inferences/insights from the extensive studies but focus on the interpretation of its similar to 12-yr quasi-periodic optical outbursts (QPOOs) and high energy emission mechanisms. The QPOOs in one model are attributed to the disk-impact related to dynamics of the binary SMBHs while alternative models attribute it to the geometrical effect related to the precession of a single jet or double jets. We discuss implications of the new spectral features reported during the 2015-2017 multi-wavelength high activity of the source-a break in the NIR-optical spectrum and hardening of the MeV-GeV emission accompanied by a shift in the location of its peak, in the context of the two. The reported NIR-optical break nicely fits the description of a standard accretion disk emission from an SMBH of mass similar to 1010M circle dot while the time of its first appearance at the end of May, 2013 (MJD 56439) is in close coincidence with the time of impact predicted by the disk-impact binary SMBH model. This spectral and temporal coincidence with the model parameters of the disk-impact binary SMBH model provides independent evidence in favor of the model over the geometrical models which argue for a total central-engine mass in the range of 107-9M circle dot. On the other hand, the MeV-GeV spectral change is naturally reproduced by the inverse Compton scattering of photons from the broad-line region and is consistent with the detection of broad emission lines during the previous cycles of quasi-periodic outbursts. Combining this with previous SED studies suggests that in, OJ 287, the MeV-GeV emission results from external Comptonization. (AU)

FAPESP's process: 15/13933-0 - Probing relativistic jets and high energy emission through Multi-wavelength observation analysis
Grantee:Pankaj Kushwaha
Support Opportunities: Scholarships in Brazil - Post-Doctorate