Deciphering the Multi-Wavelength Flares of the Most Distant Very High-Energy (>100 GeV) Gamma-ray Emitting Blazar

TL;DR

This paper investigates the multi-wavelength flaring activity of a distant gamma-ray blazar, revealing insights into jet emission mechanisms, spectral evolution, and the location of gamma-ray emission regions through detailed modeling and analysis.

Contribution

It provides a comprehensive multi-wavelength analysis of a distant FSRQ, modeling its emission with leptonic processes and identifying the emission region outside the broad-line region.

Findings

Detection of two VHE epochs and gamma-ray flaring episodes

Spectral energy distribution evolution and X-ray spectral changes

Emission region located outside the broad-line region within the dusty torus

Abstract

This study analyzes the multi-wavelength flaring activity of the distant flat spectrum radio quasar (FSRQ) OP 313 (z=0.997) during November 2023 to March 2024, using data from Fermi-Large Area Telescope, Swift X-ray Telescope, and Ultraviolet and Optical Telescope. The analysis highlights two significant very high energy(VHE) detection epochs and GeV gamma-ray flaring episodes, providing insight into jet emission processes and radiative mechanisms. Key findings include broadband spectral energy distribution (SED) evolution, including enigmatic X-ray spectral changes. Modeling of the multi-wavelength SED with a one-zone leptonic radiative processes attributes the emissions to synchrotron radiation, Synchrotron Self-Compton (SSC), and External Compton (EC) mechanisms, with torus photons as the primary source for EC processes. The results suggest that the gamma-ray emitting region lies outside the broad-line region but within the dusty torus. Furthermore, we find that the radiated power is significantly smaller than the total jet power, suggesting that most of the bulk energy remains within the jet even after passing through the blazar emission zone. These findings advance our understanding of particle acceleration, jet dynamics, and photon field interactions in FSRQs.