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arXiv · 2408.13052

Detection of a Transient Quasi-periodic Oscillation in $\gamma$-Rays from Blazar PKS 2255-282

Ajay Sharma·Anuvab Banerjee·Avik Kumar Das·Avijit Mandal·Debanjan Bose
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Abstract

We conducted a comprehensive variability analysis of the blazar PKS 2255-282 using Fermi-LAT observations spanning over four years, from MJD 57783.5 to 59358.5. Our analysis revealed a transient quasi-periodic oscillation (QPO) with a period of 93$\pm$2.6 days. We employed a variety of Fourier-based methods, including the Lomb-Scargle Periodogram (LSP) and Weighted Wavelet Z-Transform (WWZ), as well as time domain analysis techniques such as Seasonal and Non-Seasonal Autoregressive Integrated Moving Average (ARIMA) models and the Stochastic modeling with Stochastically Driven Damped Harmonic Oscillator (SHO) models. Consistently, the QPO with a period of 93 days was detected across all methods used. The observed peak in LSP and time-averaged WWZ plots has a significance level of 4.06$\sigma$ and 3.96$\sigma$, respectively. To understand the source of flux modulations in the light curve, we explored various physical models. A plausible scenario involves the precession of the jet with a high Lorentz factor or the movement of a plasma blob along a helical trajectory within the relativistic jet.

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Ajay Sharma, Anuvab Banerjee, Avik Kumar Das, Avijit Mandal, Debanjan Bose. 2024-08-23. Detection of a Transient Quasi-periodic Oscillation in $\gamma$-Rays from Blazar PKS 2255-282. https://arxiv.org/abs/2408.13052

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