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Related papers: Potential periodic signals in blazars: significanc…

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We present a study on the detection and characterization of transient quasi-periodic oscillations (QPOs) in the $\gamma$-ray emission of blazars 4C +31.03, MG1 J123931+0443, and PKS 1622$-$253. Using light curves derived from \textit{Fermi}…

High Energy Astrophysical Phenomena · Physics 2025-12-11 P. Penil , J. Otero-Santos , A. Circiello , A. Banerjee , S. Buson , A. Rico , M. Ajello , S. Adhikari

The search for periodic signals from blazars has become an actively pursued field of research in recent years. This is because periodic signals bring us information about the processes occurring near the innermost regions of blazars, which…

High Energy Astrophysical Phenomena · Physics 2020-02-11 Gopal Bhatta

Transient quasi-periodic oscillations (QPOs) are extremely interesting observational phenomena. However, the precise physical mechanisms leading to their generation are still hotly debated. We performed a systematic search for transient QPO…

High Energy Astrophysical Phenomena · Physics 2024-10-01 Junping Chen , Jinjie Yu , Weitian Huang , Nan Ding

We investigate the possible presence of quasi-periodic oscillation (QPO) signals in 2103 blazars from the Zwicky Transient Facility (ZTF) time-domain survey. We detect a low-frequency QPO signal in five blazars observed over these…

Astrophysics of Galaxies · Physics 2023-10-05 Anuvab Banerjee , Vibhore Negi , Ravi Joshi , Nagendra Kumar , Paul J. Wiita , Hum Chand , Nikita Rawat , Xue-Bing Wu , Luis C. Ho

This study explores transient quasi-periodic oscillations (QPOs) in the $\gamma$-ray emission of two blazars, PMN J0531$-$4827 and PKS 1502+106, using over a decade of Fermi Large Area Telescope observations. The analysis focuses on…

High Energy Astrophysical Phenomena · Physics 2025-08-20 P. Penil , J. Otero-Santos , A. Banerjee , S. Buson , A. Rico , M. Ajello , S. Adhikari

Quasi-periodic oscillations (QPO) originating from innermost regions of blazars can provide unique perspective of some of the burning issues in blazar studies including disk-jet connection, launch of relativistic jets from the central…

High Energy Astrophysical Phenomena · Physics 2019-06-12 Gopal Bhatta

In this work, we analyzed the long term gamma-ray data by a Fermi Large Area Telescope (Fermi-LAT) of blazar S2 0109+22, ranging from 2008 to 2023. The quasi-periodic oscillations (QPOs) of blazars aided in investigating the physical…

High Energy Astrophysical Phenomena · Physics 2023-07-17 Haoyang Zhang , Fan Wu , Benzhong Dai

We systematically search for quasiperiodic oscillatory (QPO) signals on the month timescale among the 1525 sources given in the Fermi Large Area Telescope Light Curve Repository. We find a transient QPO of 31.3$\pm$1.8 days in the gamma-ray…

High Energy Astrophysical Phenomena · Physics 2022-10-18 Junping Chen , Tingfeng Yi , Yunlu Gong , Xing Yang , Zhihui Chen , Xin Chang , Lisheng Mao

In this work, we report periodicity search analyses in the gamma-ray light curve of the blazar S4 0954+658 monitoring undertaken by the Fermi Large Area Telescope (LAT). Four analytical methods and a tool are adopted to detect any periodic…

High Energy Astrophysical Phenomena · Physics 2023-05-31 Yunlu Gong , Shiting Tian , Liancheng Zhou , Tingfeng Yi , Jun Fang

The detection of periodicities in light curves of active galacticnuclei (AGN) could have profound consequences for our understanding of the nature and radiation physics of these objects. At high energies (HE; E>100 MeV) 5 blazars (PG…

High Energy Astrophysical Phenomena · Physics 2020-02-26 F. Ait Benkhali , W. Hofmann , F. M. Rieger , N. Chakraborty

This work present the results of a multi-epoch observational study of the blazar S5\,1803+784, carried out from 2019 to 2023. The analysis is based on simultaneous data obtained from the Swift/UVOT/XRT, ASAS-SN, and Fermi-LAT instruments. A…

High Energy Astrophysical Phenomena · Physics 2025-03-27 Javaid Tantry , Ajay Sharma , Zahir Shah , Naseer Iqbal , Debanjan Bose

While there has been an increase in interest in the possibility of quasi-periodic oscillations (QPOs) in blazars, the search has hitherto been restricted to sources with well-sampled light curves. Objects with light curves that include gaps…

High Energy Astrophysical Phenomena · Physics 2024-09-18 M. A. Hashad , Amr A. El-Zant , Y. Abdou , H. M. Badran

Based on the long-term light curves collected from the Catalina Sky Survey (CSS) (from 2005 to 2013) and the All-Sky Automated Survey for Supernovae (ASAS-SN) (from 2014 to 2018), optical quasi-periodic oscillations (QPOs) about 300 days…

High Energy Astrophysical Phenomena · Physics 2022-08-17 Qi Zheng , Xueguang Zhang , Qirong Yuan

Study of quasi-periodic oscillations (QPO) in blazars is one of the crucial methods for gaining insights into the workings of the central engines of active galactic nuclei. QPOs with various characteristic time scales have been observed in…

High Energy Astrophysical Phenomena · Physics 2023-03-08 Banerjee , Anuvab , Sharma , Ajay , Mnadal , Avijit , Das , Avik Kumar , Bhatta , Gopal , Bose , Debanjan

A comprehensive analysis of quasi-periodic oscillations (QPOs) in the gamma-ray emissions of blazars. Utilizing 15 years of Fermi-LAT observations of seven blazars in our sample, we identify both long-term and transient quasi-periodic…

High Energy Astrophysical Phenomena · Physics 2025-05-30 Ajay Sharma , Sakshi Chaudhary , Aishwarya Sarath , Debanjan Bose

The continuous monitoring capability of Fermi-LAT has enabled the exploration of Quasi-Periodic Oscillations (QPOs) in the $\gamma$-ray light curve of blazar that has given a new perspective to probe these sources over a wide range of time…

High Energy Astrophysical Phenomena · Physics 2023-07-05 Avik Kumar Das , Raj Prince , Alok C. Gupta , Pankaj Kushwaha

In this work, we explore the long-term variability properties of the blazar PKS 0219-164 in the radio and the $\gamma$-ray regime, utilizing the OVRO 15 GHz and the \fermi/LAT observations from the period 2008--2017. We found that…

High Energy Astrophysical Phenomena · Physics 2017-09-20 Gopal Bhatta

Blazar variability may be driven by stochastic processes. On the other hand, quasi-periodic oscillation (QPO) behaviors are recently reported to be detected in $\it{Fermi}$-LAT data of blazars. However, the significances of these QPO…

High Energy Astrophysical Phenomena · Physics 2021-02-10 Shenbang Yang , Dahai Yan , Pengfei Zhang , Benzhong Dai , Li Zhang

Variability is a typical observation feature of Fermi blazars, sometimes it shows quasi-periodic oscillation (QPO). In this work, we obtained 5-day binned light curves (with a time coverage of $\sim$ 12.9 yr) for S5 1044+71 based on Fermi…

High Energy Astrophysical Phenomena · Physics 2022-04-27 G. G. Wang , J. T. Cai , J. H. Fan

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…

High Energy Astrophysical Phenomena · Physics 2024-08-26 Ajay Sharma , Anuvab Banerjee , Avik Kumar Das , Avijit Mandal , Debanjan Bose
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