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

Abstract

A diverse range of 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 $\sim$ 12-yr 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 $\sim 10^{10}{M}_{\odot }$ while the time of its first appearance in end-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 a total central-engine mass in the range of $10^{7-9}{\mathrm{M}}_{\odot }$. 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, MeV-GeV emission results from external Comptonization.

12 pages, 1 figure (submitted to Galaxies)

References in corpus (12)

• The power of relativistic jets is larger than the luminosity of their accretion disks
• A massive binary black-hole system in OJ287 and a test of general relativity
• The blazar sequence: a new perspective
• Shedding New Light on the 3C 273 Jet with the Spitzer Space Telescope
• Hadronic models of blazars require a change of the accretion paradigm
• Detection of Possible Quasi-periodic Oscillations in the Long-term Optical Light Curve of the BL Lac Object OJ 287
• Location of Gamma-ray emission and magnetic field strengths in OJ 287
• Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state
• Gamma-ray Flux Distribution and Non-linear behavior of Four LAT Bright AGNs
• Multi-wavelength temporal and spectral variability of the blazar OJ 287 during and after the December 2015 flare: a major accretion disc contribution
• Multiband optical variability of the blazar OJ 287 during its outbursts in 2015 -- 2016
• Strong Soft X-ray Excess in 2015 XMM-Newton Observation of BL--Lac OJ~287

Cited by in corpus (13)

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• A Possible $\gamma$-ray Quasi-periodic Oscillation of $\sim$ 314 days in the Blazar OJ 287
• Long Term Multi-band Near Infra-Red Variability of the Blazar OJ 287 during 2007--2021
• Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability
• Spectral States of OJ 287 blazar from Multi-wavelength Observations with $AstroSat$
• A hadronic emission model for black hole-disc impacts in the blazar OJ 287
• Blazar OJ 287 After First VHE Activity: Tracking the Re-emergence of the HBL like Component in 2020
• Short-term X-ray Variability during Different Activity Phases of Blazars S5 0716+714 and PKS 2155-304
• X-ray Flux and Spectral Variability of the Blazar OJ 287 with Suzaku
• The blazar OJ 287 jet from parsec- to kiloparsec-scales
• On the Spectral Changes of OJ 287: The Lowest X-ray state Spectrum -- extended at Optical-UV and Hard at X-rays
• The First VHE Activity of OJ 287 and the Extragalactic Background Light