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arXiv · 2603.06116

Detection of quasi-periodic oscillations in the 37 GHz radio light curve of the blazar Ton 599 during 1990-2020

Alok C. Gupta·Alexandr E. Volvach·Shubham Kishore·Larisa N. Volvach·Paul J. Wiita·Lang Cui·Mauri J. Valtonen·Sandeep K. Mondal·Haritma Gaur
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Abstract

Blazars are a subclass of radio-loud active galactic nuclei (AGNs) that display strong multi-wavelength variability on diverse timescales ranging from years down to minutes. In the last 1.5 decades, there have been occasional detections of quasi-periodic oscillations in several blazars in their time series data. We search for quasi-periodic oscillations (QPOs) in the 37 GHz radio band light curve of the flat-spectrum radio quasar Ton~599 made at the RT-22 radio telescope in Simeiz, Crimea, from 1990 to 2020. To identify and quantify the QPO nature of this radio light curve of Ton 599, we used the Lomb-Scargle periodogram (LSP), REDFIT, and weighted wavelet Z-transform (WWZ) analyses. We report the detection of a likely QPO of about 2.4 years in the 37 GHz radio light curves of Ton 599. We briefly discuss possible emission models for radio-loud active galactic nuclei that could explain such QPOs with periods of a few years.

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Alok C. Gupta, Alexandr E. Volvach, Shubham Kishore, Larisa N. Volvach, Paul J. Wiita, Lang Cui, Mauri J. Valtonen, Sandeep K. Mondal, Haritma Gaur. 2026-03-06. Detection of quasi-periodic oscillations in the 37 GHz radio light curve of the blazar Ton 599 during 1990-2020. https://arxiv.org/abs/2603.06116

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