Probing the Jet Power of the Blazar OJ 287 from Multiwavelength Broadband SED Modelling

Abstract

OJ 287 is one of the most extensively studied blazars and exhibits strong variability across the entire electromagnetic spectrum, making it an ideal laboratory for investigating the physics of relativistic jets and their connection to the central supermassive black hole. In this work, we explore the jet energetics of OJ 287 through detailed multiwavelength spectral energy distribution (SED) modelling using quasi-simultaneous observations spanning the optical/UV, X-ray, and high-energy γ-ray bands. The observed broadband emission is interpreted within a one-zone leptonic framework using the composite spectral model and the intrinsic jet emission arises from synchrotron and inverse Compton radiation processes. In particular, the underlying electron energy distribution is modeled using a broken power-law formulation to characterize the low- and high-energy particle populations responsible for the observed radiation. Both synchrotron self-Compton (SSC) and external Compton (EC) mechanisms are considered to reproduce the X-ray and high-energy emission components. By fitting the model to the observed data, we derive the fundamental physical parameters of the jet, including the magnetic field strength, size of the emission region, bulk Lorentz factor, Doppler boosting factor, and the properties of the relativistic electron population. Using the best-fitting parameters, we estimate the total jet power and decompose it into contributions from relativistic electrons, cold protons, magnetic fields, and radiative output. Our results suggest that the jet of OJ 287 is highly energetic, with the kinetic power predominantly carried by relativistic particles along with a significant magnetic contribution. The inferred total jet power is comparable to or greater than the accretion power estimated from the optical–UV emission, supporting efficient jet-launching processes in supermassive black hole systems.