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We calculate the time dependent electron distribution under the assumption of continuous injection of new relativistic particles, and assuming radiative cooling (by sinchrotron and inverse Compton) and particle escape. Resulting photon…

Astrophysics · Physics 2007-05-23 Marco Chiaberge , Gabriele Ghisellini

We study the stochastic variation of blazar emission under a 2-D spatially resolved leptonic jet model we previously developed. Random events of particle acceleration and injection in small zones within the emission region are assumed to be…

High Energy Astrophysical Phenomena · Physics 2016-03-23 Xuhui Chen , Martin Pohl , Markus Böttcher , Shan Gao

This paper presents the gamma-ray spectral and timing results from the long-term regular observations of Mrk 421 with the Large Area Telescope (LAT) onboard Fermi during 2008 August - 2023 August. We discerned six periods the relatively…

High Energy Astrophysical Phenomena · Physics 2025-03-05 B. Kapanadze , A. Gurchumelia , M. Aller

This paper presents the results of a detailed timing and spectral analysis of the TeV-detected blazar 1ES 1218+304, focused on the observations performed with the different instruments onboard the Neil Gehrels Swift Observatory in the…

Astrophysics of Galaxies · Physics 2025-04-22 B. Kapanadze , A. Gurchumelia , M. Aller

Mrk501 is a very high-energy (VHE) gamma-ray blazar located at z=0.034. During a period of two weeks in July 2014, the highest X-ray activity of Mrk501 was observed in ~14 years of operation of the Neil Gehrels Swift Gamma-ray Burst…

High Energy Astrophysical Phenomena · Physics 2021-03-17 MAGIC Collaboration , V. A. Acciari , S. Ansoldi , L. A. Antonelli , A. Babić , B. Banerjee , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , E. Bernardini , A. Berti , J. Besenrieder , W. Bhattacharyya , C. Bigongiari , O. Blanch , G. Bonnoli , G. Busetto , R. Carosi , G. Ceribella , S. Cikota , S. M. Colak , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , V. D'Elia , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , M. Delfino , J. Delgado , F. Di Pierro , E. Do Souto Espiñera , A. Domínguez , D. Dominis Prester , M. Doro , V. Fallah Ramazani , A. Fattorini , A. Fernández-Barral , G. Ferrara , D. Fidalgo , L. Foffano , M. V. Fonseca , L. Font , C. Fruck , D. Galindo , S. Gallozzi , R. J. García López , M. Garczarczyk , S. Gasparyan , M. Gaug , P. Giammaria , N. Godinović , D. Guberman , D. Hadasch , A. Hahn , T. Hassan , J. Herrera , J. Hoang , D. Hrupec , S. Inoue , K. Ishio , Y. Iwamura , H. Kubo , J. Kushida , D. Kuveždić , A. Lamastra , D. Lelas , F. Leone , E. Lindfors , S. Lombardi , F. Longo , M. López , A. López-Oramas , B. Machado de Oliveira Fraga , C. Maggio , P. Majumdar , M. Makariev , M. Mallamaci , G. Maneva , M. Manganaro , L. Maraschi , M. Mariotti , M. Martínez , S. Masuda , D. Mazin , M. Minev , J. M. Miranda , R. Mirzoyan , E. Molina , A. Moralejo , V. Moreno , E. Moretti , P. Munar-Adrove r , V. Neustroev , A. Niedzwiecki , M. Nievas Rosillo , C. Nigro , K. Nilsson , D. Ninci , K. Nishijima , K. Noda , L. Nogués , S. Paiano , J. Palacio , D. Paneque , R. Paoletti , J. M. Paredes , G. Pedaletti , P. Peñil , M. Peresano , M. Persic , P. G. Prada Moroni , E. Prandini , I. Puljak , J. R. Garcia , M. Ribó , J. Rico , C. Righi , A. Rugliancich , L. Saha , N. Sahakyan , T. Saito , K. Satalecka , T. Schweizer , J. Sitarek , I. Šnidarić , D. Sobczynska , A. Somero , A. Stamerra , M. Strzys , T. Surić , F. Tavecchio , P. Temnikov , T. Terzić , M. Teshima , N. Torres-Albá , S. Tsujimoto , J. van Scherpenberg , G. Vanzo , M. Vazquez Acosta , I. Vovk , M. Will , D. Zarić , FACT Collaboration , : , A. Arbet-Engels , D. Baack , M. Balbo , A. Biland , M. Blank , T. Bretz , K. Bruegge , M. Bulinski , J. Buss , M. Doerr , D. Dorner , S. Einecke , D. Elsaesser , D. Hildebrand , L. Linhoff , K. Mannheim , S. Mueller , D. Neise , A. Neronov , M. Noethe , A. Paravac , W. Rhode , B. Schleicher , F. Schulz , K. Sedlaczek , A. Shukla , V. Sliusar , E. von Willert , R. Walter , C. Wendel , A. Tramacere , A. Lien , M. Perri , F. Verrecchia , M. Armas Padilla , C. Leto , A. Lähteenmäki , M. Tornikoski , J. Tammi

The results of a BeppoSAX TOO observation of the BL Lac object Mkn421 during a high intensity state are reported and compared with monitoring X-ray data collected with the BeppoSAX Wide Field Cameras (WFC) and the RXTE All Sky Monitor(ASM).…

Blazars' non-thermal emission shows rapid variability across all wavelengths, so spectral energy distributions (SEDs) built from quasi-simultaneous data are crucial for revealing the jets physical properties. In this work, we construct…

High Energy Astrophysical Phenomena · Physics 2026-05-22 Yi Zhong , Zhujian Wan , Rui Xue , Hubing Xiao , Dingrong Xiong , Ze-Rui Wang

We calculate durations and spectral paramaters for 218 Swift bursts detected by the BAT instrument between and including GRBs 041220 and 070509, including 77 events with measured redshifts. Incorporating prior knowledge into the spectral…

Astrophysics · Physics 2009-11-13 Nathaniel R. Butler , Daniel Kocevski , Joshua S. Bloom , Jason L. Curtis

Aims. The observation of gamma -ray flares from blazar 0836+710 in 2011, following a period of quiescence, offered an opportunity to study correlated activity at different wavelengths for a high-redshift (z=2.218) active galactic nucleus.…

High Energy Astrophysical Phenomena · Physics 2015-06-16 A. Akyuz , D. J. Thompson , D. Donato , J. S. Perkins , L. Fuhrmann , E. Angelakis , J. A. Zensus , S. Larsson , K. Sokolovsky , O. Kurtanidze

An explanation is proposed for the fact that in LMXBs the correlation between most observable X-ray spectral and timing parameters (such as kHz QPO frequency) on the one hand, and Lx on the other, while generally good in a given source on a…

Astrophysics · Physics 2009-11-06 M. van der Klis

We present a long-term strong correlation between millimeter (mm) radio and $\gamma$-ray emission in the flat-spectrum radio quasar (FSRQ) PKS 1424-418. The mm$-\gamma$-ray connection in blazars is generally thought to originate from the…

High Energy Astrophysical Phenomena · Physics 2024-12-02 Dae-Won Kim , Eduardo Ros , Matthias Kadler , Thomas P. Krichbaum , Guang-Yao Zhao , Florian Rösch , Andrei P. Lobanov , J. Anton Zensus

Variability studies of jetted AGN, in particular blazars, have been used to gain a better understanding of the particle acceleration mechanisms in jets. However, statistical methods used for the characterization of variability often rely on…

High Energy Astrophysical Phenomena · Physics 2025-12-23 Andrea Gokus , Rebecca Phillipson

To better understand long-term flare activity, we present a statistical study on soft X-ray flares from May 1976 to May 2008. It is found that the smoothed monthly peak fluxes of C-class, M-class, and X-class flares have a very noticeable…

Solar and Stellar Astrophysics · Physics 2015-03-17 X. L. Yan , L. H. Deng , Z. Q. Qu , C. L. Xu

We conduct X-ray spectral fits on 184 likely counterparts to Fermi-LAT 3FGL unassociated sources. Characterization and classification of these sources allows for more complete population studies of the high-energy sky. Most of these X-ray…

High Energy Astrophysical Phenomena · Physics 2021-03-02 Stephen Kerby , Amanpreet Kaur , Abraham D. Falcone , Michael C. Stroh , Elizabeth C. Ferrara , Jamie A. Kennea , Joseph Colosimo

We investigate the characteristics of bright flares for a sample of supergiant fast X-ray transients and their relation to the orbital phase. We have retrieved all Swift/BAT Transient Monitor light curves, and collected all detections in…

We conducted a comprehensive temporal and spectral study of the FSRQ PKS 0805-07 by using the broadband observations from the Fermi-LAT and Swift-XRT/UVOT instruments over the period MJD 54684-60264. The 3-day binned $\gamma$-ray light…

High Energy Astrophysical Phenomena · Physics 2024-12-13 Sikandar A. Dar , Zahir Shah , Ranjeev Misra , Naseer Iqbal

High-redshift blazars are among the most powerful objects in the Universe. The spectral and temporal properties of thirty-three distant blazars ($z>2.5$) detected in the high energy $\gamma$-ray band are investigated by analyzing the {\it…

High Energy Astrophysical Phenomena · Physics 2020-08-25 N. Sahakyan , D. Israyelyan , G. Harutyunyan , M. Khachatryan , S. Gasparyan

Several models have been suggested to explain the fast gamma-ray variability observed in blazars, but its origin is still debated. One scenario is magnetic reconnection, a process that can efficiently convert magnetic energy to energy of…

High Energy Astrophysical Phenomena · Physics 2021-09-20 J. Jormanainen , T. Hovatta , E. Lindfors , I. Christie , M. Petropoulou , I. Liodakis

Exceptionally strong and long lasting flaring activity of the blazar Markarian 421 (Mrk 421) occurred between January and March 2001. Based on the excellent signal-to-noise ratio of the data we derive the energy spectrum between 260 GeV -…

During the observation period 1997, the nearby Blazar Mkn 501 showed extremely strong emission and high variability. We examine multiwavelength aspects of this event using radio, optical, soft and hard X-ray and TeV data. We concentrate on…

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