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{We focus on characterizing the high-energy emission mechanisms of blazars by analyzing the variability in the radio band of the light curves of more than a thousand sources. We are interested in assigning complexity parameters to these…

Data Analysis, Statistics and Probability · Physics 2022-05-11 Belén Acosta-Tripailao , Walter Max-Moerbeck , Denisse Pastén , Pablo S. Moya

We studied the optical variability of 241 BL Lacs and 83 flat-spectrum radio quasars (FSRQ) from the 4LAC catalog using data from the Tomo-e Gozen Northern Sky Transient Survey, with $\sim$ 50 epochs per blazar on average. We excluded…

Blazars dominate the extragalactic $\gamma$-ray sky and show pronounced flares. Using public Fermi-LAT light curves for 732 blazars with secure redshifts, I implement an automated pipeline to identify and characterize $\gamma$-ray bursts…

High Energy Astrophysical Phenomena · Physics 2025-08-29 Matteo Cerruti

Active galactic nuclei (AGN) are some of the brightest and most variable objects in the Universe. Those with relativistic jets observed at small viewing angles are blazars. Due to Doppler boosting, blazars exhibit extreme stochastic…

Blazars can be divided into two subtypes, flat spectrum radio quasars (FSRQs) and BL Lac objects, which have been distinguished phenomenologically by the strength of their optical emission lines, while their physical nature and relationship…

High Energy Astrophysical Phenomena · Physics 2020-07-22 Makoto Uemura , Taisei Abe , Yurika Yamada , Shiro Ikeda

A 2.1-year periodic oscillation of the gamma-ray flux from the blazar PG 1553+113 has previously been tentatively identified in almost 7 year of data from the Fermi Large Area Telescope. After 15 years of Fermi sky-survey observations,…

We discuss the time-series behavior of 8 extragalactic 3FGL sources away from the Galactic plane (i.e., $\mid b\mid \geq 10^{\circ}$) whose uncertainty ellipse contains a single X-ray and one radio source. The analysis was done using the…

High Energy Astrophysical Phenomena · Physics 2021-07-14 P. Nkundabakura , J. D. Kamanzi , J. D. Mbarubucyeye , T. Mutabazi

Machine learning has emerged as a powerful tool in the field of gamma-ray astrophysics. The algorithms can distinguish between different source types, such as blazars and pulsars, and help uncover new insights into the high-energy universe.…

High Energy Astrophysical Phenomena · Physics 2024-01-05 Gopal Bhatta , Sarvesh Gharat , Abhimanyu Borthakur , Aman Kumar

Blazars are a subclass of radio-loud active galactic nuclei (AGNs), where the jet is aligned close to the line of sight. Blazars emission is dominated by non-thermal processes, where Doppler boosted radiation originates from a relativistic…

High Energy Astrophysical Phenomena · Physics 2021-08-19 Jakub Juryšek , Vitalii Sliusar , Dimitri Moulin , Roland Walter

The uncharted territory of the high-redshift ($z\gtrsim3$) Universe holds the key to understand the evolution of quasars. In an attempt to identify the most extreme members of the quasar population, i.e., blazars, we have carried out a…

High Energy Astrophysical Phenomena · Physics 2020-07-22 Vaidehi S. Paliya , M. Ajello , H. -M. Cao , M. Giroletti , Amanpreet Kaur , Greg Madejski , Benoit Lott , D. Hartmann

Blazars show variability on timescales ranging from minutes to years, the former being comparable to and in some cases even shorter than the light-crossing time of the central black hole. The observed gamma-ray lightcurves can be described…

High Energy Astrophysical Phenomena · Physics 2017-07-10 Michael O' Riordan , Asaf Pe'er , Jonathan C. McKinney

Blazars are a sub-population of quasars whose jets are nearly aligned with the line-of-sight, which tend to exhibit multi-wavelength variability on a variety of timescales. Quasi-periodic variability on year-like timescales has been…

High Energy Astrophysical Phenomena · Physics 2018-09-05 A. Miguel Holgado , Alberto Sesana , Angela Sandrinelli , Stefano Covino , Aldo Treves , Xin Liu , Paul Ricker

We present $\gamma$-ray, X-ray, ultraviolet, optical, and near-infrared light curves of 33 $\gamma$-ray bright blazars over four years that we have been monitoring since 2008 August with multiple optical, ground-based telescopes and the…

Context. Investigation of the hard X-ray emission properties of blazars is key to the understanding of the central engine of the sources and associated jet process. In particular, simultaneous spectral and timing analyses of the intra-day…

High Energy Astrophysical Phenomena · Physics 2018-11-14 Gopal Bhatta , Maksym Mohorian , Illya Bilinsky

The extragalactic $\gamma$-rays sky observed by Fermi-Large Area Telescope (LAT) is dominated by blazars. In the fourth release of the Fermi-LAT Point Source Catalog (4FGL), are sources showing a multifrequency behavior similar to that of…

Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the twisting jet model presented in previous works to explain…

High Energy Astrophysical Phenomena · Physics 2024-12-03 C. M. Raiteri , M. Villata , M. I. Carnerero , S. O. Kurtanidze , D. O. Mirzaqulov , E. Benítez , G. Bonnoli , D. Carosati , J. A. Acosta-Pulido , I. Agudo , T. S. Andreeva , G. Apolonio , R. Bachev , G. A. Borman , V. Bozhilov , L. F. Brown , W. Carbonell , C. Casadio , W. P. Chen , G. Damljanovic , S. A. Ehgamberdiev , D. Elsaesser , J. Escudero , M. Feige , A. Fuentes , D. Gabellini , K. Gazeas , M. Giroletti , T. S. Grishina , A. C. Gupta , M. A. Gurwell , V. A. Hagen-Thorn , G. M. Hamed , D. Hiriart , M. Hodges , R. Z. ivanidze , D. V. Ivanov , M. D. Joner , S. G. Jorstad , M. D. Jovanovic , S. Kiehlmann , G. N. Kimeridze , E. N. Kopatskaya , Yu. A. Kovalev , Y. Y. Kovalev , O. M. Kurtanidze , A. Kurtenkov , E. G. Larionova , A. Lessing , H. C. Lin , J. M. López , C. Lorey , J. Ludwig , N. Marchili , A. Marchini , A. P. Marscher , K. Matsumoto , W. Max-Moerbeck , B. Mihov , M. Minev , M. G. Mingaliev , A. Modaressi , D. A. Morozova , F. Mortari , T. V. Mufakharov , I. Myserlis , M. G. Nikolashvili , T. J. Pearson , A. V. Popkov , I. A. Rahimov , A. C. S. Readhead , D. Reinhart , R. Reeves , S. Righini , F. D. Romanov , S. S. Savchenko , E. Semkov , E. V. Shishkina , L. A. Sigua , L. Slavcheva-Mihova , Yu. V. Sotnikova , R. Steineke , M. Stojanovic , A. Strigachev , A. Takey , E. Traianou , Yu. V. Troitskaya , I. S. Troitskiy , A. L. Tsai , A. Valcheva , A. A. Vasilyev , G. Verna , O. Vince , K. Vrontaki , Z. R. Weaver , J. Webb , Q. X. Yuldoshev , E. Zaharieva , A. V. Zhovtan

Flaring activity from the jets of active galactic nuclei has been studied for several decades, closely related to the loading and evolution of the jet. In this work, we focus on the sub-hundred parsec jet region, well traced by non-thermal…

High Energy Astrophysical Phenomena · Physics 2026-04-07 Alina Kochocki , Emma Kun , Sam Hori

Blazars are known to show periods of quiescence followed by outbursts visible throughout the electromagnetic spectrum. We present a novel maximum likelihood approach to capture this bimodal behavior by examining blazar radio variability in…

High Energy Astrophysical Phenomena · Physics 2017-03-30 I. Liodakis , V. Pavlidou , T. Hovatta , W. Max-Moerbeck , T. J. Pearson , J. L. Richards , A. C. S. Readhead

Blazar jet structure can be indirectly resolved by analyzing the multiwavelength variability. In this work, we analyze the long-term variability of blazars in radio, optical and X-ray energies with the Gaussian process (GP) method. The…

High Energy Astrophysical Phenomena · Physics 2023-02-22 Haiyun Zhang , Dahai Yan , Li Zhang

We present the results of the power spectral density (PSD) analysis for the blazars Mrk\,421 and PKS\,2155$-$304, using good-quality, densely sampled light curves at multiple frequencies, covering 17 decades of the electromagnetic spectrum,…

High Energy Astrophysical Phenomena · Physics 2020-04-22 Arti Goyal
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