Related papers: Rapid X-ray Variability in Mkn 421 during a Multiw…

VLBA monitoring of Mrk 421 at 15 and 24 GHz during 2011

We present a preliminary analysis of new high resolution radio observations of the nearby TeV blazar Markarian 421 (z=0.031). This study is part of an ambitious multifrequency campaign, with observations in sub-mm (SMA), optical/IR (GASP),…

High Energy Astrophysical Phenomena · Physics 2012-05-03 R. Lico , M. Giroletti , M. Orienti , G. Giovannini , B. Cotton , P. Edwards , L. Fuhrmann , T. Krichbaum , K. Sokolovsky , S. Jorstad , A. Marscher , M. Kino , Y. Kovalev , D. Paneque , M. A. Perez-Torres , G. Piner

A multiwavelength view of the flaring state of PKS 2155-304 in 2006

Multiwavelength (MWL) observations of the blazar PKS 2155-304 during two weeks in July and August 2006, the period when two exceptional flares at very high energies (VHE, E>= 100 GeV) occurred, provide a detailed picture of the evolution of…

High Energy Astrophysical Phenomena · Physics 2015-06-03 HESS Collaboration , A. Abramowski , F. Acero , F. Aharonian , A. G. Akhperjanian , G. Anton , A. Balzer , A. Barnacka , U. Barres de Almeida , Y. Becherini , J. Becker , B. Behera , W. Benbow , K. Bernlöhr , A. Bochow , C. Boisson , J. Bolmont , P. Bordas , T. Boutelier , J. Brucker , F. Brun , P. Brun , T. Bulik , I. Büsching , S. Carrigan , S. Casanova , M. Cerruti , P. M. Chadwick , A. Charbonnier , R. C. G. Chaves , A. Cheesebrough , L. -M. Chounet , A. C. Clapson , G. Coignet , G. Cologna , P. Colom , J. Conrad , N. Coudreau , M. Dalton , M. K. Daniel , I. D. Davids , B. Degrange , C. Deil , H. J. Dickinson , A. Djannati-Ataï , W. Domainko , L. O'C. Drury , F. Dubois , G. Dubus , K. Dutson , J. Dyks , M. Dyrda , P. Edwards , K. Egberts , P. Eger , P. Espigat , L. Fallon , C. Farnier , S. Fegan , F. Feinstein , M. V. Fernandes , A. Fiasson , G. Fontaine , A. Förster , M. Füßling , Y. A. Gallant , H. Gast , M. J. Gaylard , L. Gérard , D. Gerbig , B. Giebels , J. F. Glicenstein , B. Glück , P. Goret , D. Göring , S. Häffner , J. D. Hague , D. Hampf , M. Hauser , S. Heinz , G. Heinzelmann , G. Henri , G. Hermann , J. A. Hinton , A. Hoffmann , W. Hofmann , P. Hofverberg , M. Holler , D. Horns , A. Jacholkowska , O. C. de Jager , C. Jahn , M. Jamrozy , I. Jung , M. A. Kastendieck , K. Katarzyński , U. Katz , S. Kaufmann , D. Keogh , D. Khangulyan , B. Khélifi , M. Klein , D. Klochkov , W. Kluźniak , T. Kneiske , Nu. Komin , K. Kosack , R. Kossakowski , P. Kubanek , H. Laffon , G. Lamanna , D. Lennarz , J. -P. Lenain , T. Lohse , A. Lopatin , C. -C. Lu , V. Marandon , A. Marcowith , J. M. Martin , J. Masbou , D. Maurin , N. Maxted , T. J. L. McComb , M. C. Medina , J. Méhault , G. Melady , N. Nguyen , R. Moderski , B. Monard , E. Moulin , C. L. Naumann , M. Naumann-Godo , M. de Naurois , D. Nedbal , D. Nekrassov , B. Nicholas , J. Niemiec , S. J. Nolan , S. Ohm , E. de Oña Wilhelmi , B. Opitz , M. Ostrowski , I. Oya , M. Panter , M. Paz Arribas , G. Pedaletti , G. Pelletier , P. -O. Petrucci , S. Pita , G. Pühlhofer , M. Punch , A. Quirrenbach , M. Raue , S. M. Rayner , A. Reimer , O. Reimer , M. Renaud , R. de los Reyes , F. Rieger , J. Ripken , L. Rob , S. Rosier-Lees , G. Rowell , B. Rudak , C. B. Rulten , J. Ruppel , F. Ryde , V. Sahakian , A. Santangelo , R. Schlickeiser , F. M. Schöck , A. Schulz , U. Schwanke , S. Schwarzburg , S. Schwemmer , M. Sikora , J. L. Skilton , H. Sol , G. Spengler , Ł. Stawarz , R. Steenkamp , C. Stegmann , F. Stinzing , K. Stycz , I. Sushch , A. Szostek , J. -P. Tavernet , R. Terrier , M. Tluczykont , A. Tzioumis , K. Valerius , C. van Eldik , G. Vasileiadis , C. Venter , L. Venter , J. P. Vialle , A. Viana , P. Vincent , H. J. Völk , F. Volpe , S. Vorobiov , M. Vorster , S. J. Wagner , M. Ward , R. White , A. Wierzcholska , M. Zacharias , A. Zajczyk , A. A. Zdziarski , A. Zech , H. -S. Zechlin

The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65

Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole…

High Energy Astrophysical Phenomena · Physics 2021-05-12 C. M. Raiteri , M. Villata , V. M. Larionov , S. G. Jorstad , A. P. Marscher , Z. R. Weaver

First detection of VHE gamma-ray emission from TXS~1515--273, study of its X-ray variability and spectral energy distribution

We report here on the first multi-wavelength (MWL) campaign on the blazar TXS 1515-273, undertaken in 2019 and extending from radio to very-high-energy gamma rays (VHE). Up until now, this blazar had not been the subject of any detailed MWL…

High Energy Astrophysical Phenomena · Physics 2021-07-21 MAGIC Collaboration , V. A. Acciari , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , M. Artero , K. Asano , D. Baack , A. Babić , A. Baquero , U. Barres de Almeida , J. A. Barrio , I. Batković , J. Becerra González , W. Bednarek , L. Bellizzi , E. Bernardini , M. Bernardos , A. Berti , J. Besenrieder , W. Bhattacharyya , C. Bigongiari , A. Biland , O. Blanch , Ž. Bošnjak , G. Busetto , R. Carosi , G. Ceribella , M. Cerruti , Y. Chai , A. Chilingarian , S. Cikota , S. M. Colak , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , G. D'Amico , V. D'Elia , P. Da Vela , F. Dazzi , A. De Angelis1 , B. De Lotto , M. Delfino , J. Delgado , C. Delgado Mendez , D. Depaoli , F. Di Pierro , L. Di Venere , E. Do Souto Espiñeira , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , D. Elsaesser , V. Fallah Ramazani , A. Fattorini , G. Ferrara , M. V. Fonseca , L. Font , C. Fruck , S. Fukami , R. J. García López , M. Garczarczyk , S. Gasparyan , M. Gaug , N. Giglietto , F. Giordano , P. Gliwny , N. Godinović , J. G. Green , D. Green , D. Hadasch , A. Hahn , L. Heckmann , J. Herrera , J. Hoang , D. Hrupec , M. Hütten , T. Inada , S. Inoue , K. Ishio , Y. Iwamura , I. Jiménez , J. Jormanainen , L. Jouvin , Y. Kajiwara , M. Karjalainen , D. Kerszberg , Y. Kobayashi , H. Kubo , J. Kushida , A. Lamastra , D. Lelas , F. Leone , E. Lindfors , S. Lombardi , F. Longo , R. López-Coto , M. López-Moya , A. López-Oramas , S. Loporchio , B. Machado de Oliveira Fraga , C. Maggio , P. Majumdar , M. Makariev , M. Mallamaci , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , M. Mariotti , M. Martínez , D. Mazin , S. Menchiari , S. Mender , S. Mićanović , D. Miceli , T. Miener , M. Minev , J. M. Miranda , R. Mirzoyan , E. Molina , A. Moralejo , D. Morcuende , V. Moreno , E. Moretti , V. Neustroev , C. Nigro , K. Nilsson , K. Nishijima , K. Noda , S. Nozaki , Y. Ohtani , T. Oka , J. Otero-Santos , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , L. Pavletić , P. Peñi , C. Perennes , M. Persic , P. G. Prada Moroni , E. Prandini , C. Priyadarshi , I. Puljak , W. Rhode , M. Ribó , J. Rico , C. Righi , A. Rugliancich , L. Saha , N. Sahakyan , T. Saito , S. Sakurai , K. Satalecka , F. G. Saturni , B. Schleicher , K. Schmidt , T. Schweizer , J. Sitarek , I. Šnidarić , D. Sobczynska , A. Spolon , A. Stamerra , D. Strom , M. Strzys , Y. Suda , T. Surić , M. Takahashi , F. Tavecchio , P. Temnikov , T. Terzić , M. Teshima , L. Tosti , S. Truzzi , A. Tutone , S. Ubach , J. van Scherpenberg , G. Vanzo , M. Vazquez Acosta , S. Ventura , V. Verguilov , C. F. Vigorito , V. Vitale , I. Vovk , M. Will , C. Wunderlich , D. Zaric , E. Bissaldi , G. Bonnoli , S. Cutini , F. D'Ammando , A. Nabizadeh , A. Marchini , M. Orienti

X-ray timing and spectral variability properties of blazars S5 0716+714, OJ 287, Mrk 501, and RBS 2070

The X-ray emission from blazars has been widely investigated using several space telescopes. In this work, we explored statistical properties of the X-ray variability in the blazars S5 0716+714, OJ 287, Mkn 501 and RBS 2070 using the…

High Energy Astrophysical Phenomena · Physics 2022-01-28 Maksym Mohorian , Gopal Bhatta , Tek P. Adhikari , Niraj Dhital , Radim Pánis , Adithiya Dinesh , Suvas C. Chaudhary , Rajesh K. Bachchan , Zdeňek Stuchlík

X-ray Emission of Mkn 421: New Clues From Its Spectral Evolution. II. Spectral Analysis and Physical Constraints

Mkn 421 was repeatedly observed with BeppoSAX in 1997-1998. The source showed a very rich phenomenology, with remarkable spectral variability. This is the second of two papers presenting the results of a thorough temporal and spectral…

Astrophysics · Physics 2009-10-31 G. Fossati , A. Celotti , M. Chiaberge , Y. H. Zhang , L. Chiappetti , G. Ghisellini , L. Maraschi , F. Tavecchio , E. Pian , A. Treves

Mrk 421 as a case study for TeV and X-ray variability in leptohadronic models

We investigate the origin of high-energy emission in blazars within the context of the leptohadronic one-zone model. We find that $\gamma$-ray emission can be attributed to synchrotron radiation either from protons or from secondary leptons…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Apostolos Mastichiadis , Maria Petropoulou , Stavros Dimitrakoudis

Mrk 421 active state in 2008: the MAGIC view, simultaneous multi-wavelength observations and SSC model constrained

Context: The blazar Markarian 421 is one of the brightest TeV gamma-ray sources of the northern sky. From December 2007 until June 2008 it was intensively observed in the very high energy (VHE, E > 100 GeV) band by the single-dish Major…

High Energy Astrophysical Phenomena · Physics 2015-05-28 J. Aleksic , E. A. Alvarez , L. A. Antonelli , P. Antoranz , M. Asensio , M. Backes , J. A. Barrio , D. Bastieri , J. Becerra Gonzalez , W. Bednarek , A. Berdyugin , K. Berger , E. Bernardini , A. Biland , O. Blanch , R. K. Bock , A. Boller , G. Bonnoli , D. Borla Tridon , I. Braun , T. Bretz , A. Canellas , E. Carmona , A. Carosi , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , L. Cossio , S. Covino , F. Dazzi , A. De Angelis , G. De Caneva , E. De Cea del Pozo , B. De Lotto , C. Delgado Mendez , A. Diago Ortega , M. Doert , A. Dominguez , D. Dominis Prester , D. Dorner , M. Doro , D. Elsaesser , D. Ferenc , M. V. Fonseca , L. Font , C. Fruck , R. J. Garcia Lopez , M. Garczarczyk , D. Garrido , G. Giavitto , N. Godinovic , D. Hadasch , D. Häfner , A. Herrero , D. Hildebrand , D. Höhne-Mönch , J. Hose , D. Hrupec , B. Huber , T. Jogler , H. Kellermann , S. Klepser , T. Krahenbuh , J. Krause , A. La Barbera , D. Lelas , E. Leonardo , E. Lindfors , S. Lombardi , A. Lopez , M. Lopez , E. Lorenz , M. Makariev , G. Maneva , N. Mankuzhiyil , K. Mannheim , L. Maraschi , M. Mariotti , M. Martinez , D. Mazin , M. Meucci , J. M. Miranda , R. Mirzoyan , H. Miyamoto , J. Moldon , A. Moralejo , P. Munar-Adrover , D. Nieto , K. Nilsson , R. Orito , I. Oya , D. Paneque , R. Paoletti , S. Pardo , J. M. Paredes , S. Partini , M. Pasanen , F. Pauss , M. A. Perez-Torres , M. Persic , L. Peruzzo , M. Pilia , J. Pochon , F. Prada , P. G. Prada Moroni , E. Prandini , I. Puljak , I. Reichardt , R. Reinthal , W. Rhode , M. Ribo , J. Rico , S. Rügamer , A. Saggion , K. Saito , T. Y. Saito , M. Salvati , K. Satalecka , V. Scalzotto , V. Scapin , C. Schultz , T. Schweizer , M. Shayduk , S. N. Shore , A. Sillanpaa , J. Sitarek , D. Sobczynska , F. Spanier , S. Spiro , A. Stamerra , B. Steinke , J. Storz , N. Strah , T. Suric , L. Takalo , H. Takami , F. Tavecchio , P. Temnikov , T. Terzic , D. Tescaro , M. Teshima , O. Tibolla , D. F. Torres , A. Treves , M. Uellenbeck , H. Vankov , P. Vogler , R. M. Wagner , Q. Weitzel , V. Zabalza , F. Zandanel , R. Zanin

Study of the variable broadband emission of Markarian 501 during the most extreme Swift X-ray activity

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

Long-term multiwavelength monitoring and reverberation mapping of NGC 2617 during a changing-look event

We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC~2617 carried out from 2016 until 2022 and covering the wavelength range from the X-ray to the near-IR. The facilities included the…

High Energy Astrophysical Phenomena · Physics 2023-08-24 V. L. Oknyansky , M. S. Brotherton , S. S. Tsygankov , A. V. Dodin , A. M. Tatarnikov , P. Du , D. -W. Bao , M. A. Burlak , N. P. Ikonnikova , V. M. Lipunov , E. S. Gorbovskoy , V. G. Metlov , A. A. Belinski , N. I. Shatsky , S. G. Zheltouhov , N. A. Maslennikova , J. -M. Wang , S. Zhai , F. -N. Fang , Y. -X. Fu , H. -R. Bai , D. Kasper , N. A. Huseynov , J. N. McLane , J. Maithil , T. E. Zastrocky , K. A. Olson , X. Chen , D. Chelouche , R. S. Oknyansky , D. A. H. Buckley , N. V. Tyurina , A. S. Kuznetsov , R. L. Rebolo , B. -X. Zhao

Rapid VHE variability in blazars

Active Galactic Nuclei (AGN) are known to show significant variability over a wide frequency range. We review observational results on the variability characteristics of blazars in the very high energy (VHE) domain, focusing on recent…

High Energy Astrophysical Phenomena · Physics 2011-04-21 Francesca Volpe , Frank M. Rieger

Long-term variability of AGN at hard X-rays

Variability at all observed wavelengths is a distinctive property of AGN. Hard X-rays provide us with a view of the innermost regions of AGN, mostly unbiased by absorption along the line of sight. Swift/BAT offers the unique opportunity to…

High Energy Astrophysical Phenomena · Physics 2015-06-17 S. Soldi , V. Beckmann , W. H. Baumgartner , G. Ponti , C. R. Shrader , P. Lubinski , H. A. Krimm , F. Mattana , J. Tueller

Multi-band optical variability of the blazar OP 313 in the outburst state during 2024-2025

We present the analysis results of flux and spectral variability of the blazar OP 313 across intra-night to short-term timescales using BVRI photometric data, gathered over 25 nights from Nov 2024 to May 2025, using two optical telescopes…

High Energy Astrophysical Phenomena · Physics 2025-09-11 P. U. Devanand , Alok C. Gupta , Karan Dogra , Shubham Kishore , Tushar Tripathi

Time dependent simulations of multiwavelength variability of the blazar Mrk 421 with a Monte Carlo multi-zone code

(abridged) We present a new time-dependent multi-zone radiative transfer code and its application to study the SSC emission of Mrk 421. The code couples Fokker-Planck and Monte Carlo methods, in a 2D geometry. For the first time all the…

High Energy Astrophysical Phenomena · Physics 2011-09-22 Xuhui Chen , Giovanni Fossati , Edison Liang , Markus Boettcher

Rapid Variability of Gamma-ray Emission from Sites near the 43 GHz Cores of Blazar Jets

Comprehensive VLBI and multi-waveband monitoring indicate that a single superluminal knot can cause a number of gamma-ray flares at different locations. However, the often very rapid variability timescale is a challenge to theoretical…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-01 Alan P. Marscher , Svetlana G. Jorstad

Influence of Energy-Dependent Particle Diffusion on the X-ray spectral curvature of MKN 421

The X-ray spectral curvature of blazars is traditionally explained by an empirical log-parabola function characterized by three parameters, namely the flux, curvature and spectral index at a given energy. Since their exact relationship with…

High Energy Astrophysical Phenomena · Physics 2018-08-08 Pranjupriya Goswami , Sunder Sahayanathan , Atreyee Sinha , Ranjeev Misra , Rupjyoti Gogoi

Exploring Emission Line Variability and Jet-Broad Line Region Interaction in the Blazar TON 599

Blazars, a highly variable Active Galactic Nuclei (AGNs) subclass, provide a unique opportunity to explore the physical processes within their relativistic jets and emission regions. In this study, we investigate the multiwavelength…

High Energy Astrophysical Phenomena · Physics 2025-11-24 Jonhatan U. Guerrero-González , Vahram Chavushyan , Víctor M. Patiño-Álvarez

Multiwavelength Variability Signatures of Relativistic Shocks in Blazar Jets

Mildly-relativistic shocks that are embedded in colliding magnetohydrodynamic flows are prime sites for relativistic particle acceleration and production of strongly variable, polarized multi-wavelength emission from relativistic jet…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Markus Boettcher , Matthew G Baring

Microquasars to AGNs: An uniform Jet variability

The long-term variability study over a range of black hole (BH) mass systems from the microquasars of stellar-mass black holes to the Active Galactic Nuclei (AGNs) of supermassive black holes, in $\gamma$-rays offers new insights into the…

High Energy Astrophysical Phenomena · Physics 2024-10-10 Ajay Sharma , Raj Prince , Debanjan Bose

A thirteen-year-long broadband view of BL Lac

We present the results of an extensive analysis of the optical, ultraviolet, X-ray and $\gamma$-ray data collected from the observations of the BL Lac objects prototype BL Lacertae carried out over a period of nearly 13 years, between…

High Energy Astrophysical Phenomena · Physics 2022-04-20 N. Sahakyan , P. Giommi