Multi-wavelength Analysis and Modeling of OJ 287 During 2017-2020

TL;DR

This study conducts a multi-wavelength analysis of blazar OJ 287 from 2017 to 2020, revealing its variability and modeling its emission to understand the physical processes, including evidence supporting a binary black hole system.

Contribution

It provides a detailed temporal, spectral, and multi-wavelength modeling analysis of OJ 287 during 2017-2020, highlighting its variability and binary black hole nature.

Findings

Moderate gamma-ray flux variability observed with Fermi-LAT.

Strong X-ray, optical, and UV flux variability during high states.

Single zone SSC model successfully explains broadband emission.

Abstract

Context. The blazar OJ 287 has been proposed as a binary black hole system based on its periodic optical outburst. Among blazars with parsec scale jets, the black hole binary systems are very rare and hence this source is very interesting to study. Aims. The BL Lac OJ 287 is an interesting object for multi-wavelength study due to its periodic outbursts. We have analyzed the optical, X-ray, and gamma-ray data of OJ 287 for the period of 2017-2020. There are several high states in optical-UV and X-ray frequencies during this period. Based on the observed variability in optical and X-ray frequencies the entire period 2017-2020 is divided into five segments, referred to as A, B, C, D, & E in this paper. A detailed temporal and spectral analysis is performed to understand the nature of its flaring activities. Methods. To understand the temporal variability in this source we have studied the intra-day, and fractional variability for all the various states, and along with that fast variability time was also estimated to understand the nature of variability. Further, the multi-wavelength SED modeling is performed to know more about the physical processes responsible for the simultaneous broadband emission and the fast variability. Results. The Fermi-LAT observations show a moderate flux level of this source in gamma-ray frequency throughout this period, though flux variability has been observed. The source has shown a strong flux variability in X-ray, optical, and UV during early 2017 and mid-2020 when the source was in a very high state. A single zone SSC emission model is considered to model the spectral energy distributions and this helps us to explore the nature of this BL Lac with binary super-massive black holes.