Possibility of Month-scale Quasi-periodic Oscillations in the Gamma-ray Light Curve of OP 313

TL;DR

This study analyzes 16.8 years of gamma-ray data from OP 313, providing tentative evidence for a future detection of a month-scale quasi-periodic oscillation, with implications for understanding jet physics.

Contribution

It presents the first analysis suggesting a potential month-scale QPO in OP 313's gamma-ray light curve using Bayesian and wavelet methods.

Findings

Tentative month-scale QPO evidence in OP 313

Curved-jet model can explain the observed behaviour

QPO detection significance limited by data length

Abstract

In this work, we report evidence suggesting the potential future detection of a month-scale quasi-periodic oscillation (QPO) in the gamma-ray light curve of OP 313. We analysed almost 16.8 years of Fermi-LAT gamma-ray data and applied the Bayesian block method to the monthly-binned light curve. We identified four high-flux states and investigated the possibility of a QPO in the fourth high-flux state (MJD 59482-60832). Using the Weighted Wavelet Z-transform (WWZ) and Lomb-Scargle Periodogram (LSP) methods, we find tentative evidence for a month-scale QPO; however, its detection significance is limited by the small number of observed cycles. With a sufficiently long data set, the QPO may be detected with higher significance in the future. We further explored possible physical origins of this potential QPO and examined several models. We found that a curved-jet model can explain the observed behaviour.