Related papers: TeV variability in blazars: how fast can it be?

Long-term optical polarization variability of the tev blazar 1es~1959+650

A detailed analysis of the optical polarimetric variability of the TeV blazar 1ES 1959+650 from 2007 October 18 to 2011 May 5 is presented. The source showed a maximum and minimum brightness states in the R-band of 14.08$\pm$0.03 mag and…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Marco Sorcia , Erika Benítez , David Hiriart , José M. López , José I. Cabrera , Raúl Mújica , Jochen Heidt , Ivan Agudo , Kari Nilsson , Michael Mommert

Extreme TeV BL Lacs: a self-consistent stochastic acceleration model

Lately a specific kind of blazars drew the attention of the gamma-ray astronomy community: the extreme TeV BL Lacs, blazars that present an extremely energetic and hard emission at very high-energy. Explaining their features is still an…

High Energy Astrophysical Phenomena · Physics 2022-10-12 Alberto Sciaccaluga , Fabrizio Tavecchio

VHE gamma-ray emission of PKS 2155-304: spectral and temporal variability

Observations of very high energy gamma-rays from blazars provide information about acceleration mechanisms occurring in their innermost regions. Studies of variability in these objects allow a better understanding of the mechanisms at play.…

High Energy Astrophysical Phenomena · Physics 2015-05-19 HESS Collaboration , A. Abramowski , F. Acero , F. Aharonian , A. G. Akhperjanian , G. Anton , U. Barres de Almeida , A. R. Bazer-Bachi , Y. Becherini , B. Behera , W. Benbow , K. Bernlohr , A. Bochow , C. Boisson , J. Bolmont , V. Borrel , J. Brucker , F. Brun , P. Brun , R. Buhler , T. Bulik , I. Busching , T. Boutelier , P. M. Chadwick , A. Charbonnier , R. C. G. Chaves , A. Cheesebrough , J. Conrad , L. -M. Chounet , A. C. Clapson , G. Coignet , L. Costamante , M. Dalton , M. K. Daniel , I. D. Davids , B. Degrange , C. Deil , H. J. Dickinson , A. Djannati-Atai , W. Domainko , L. O'C. Drury , F. Dubois , G. Dubus , J. Dyks , M. Dyrda , K. Egberts , P. Eger , P. Espigat , L. Fallon , C. Farnier , S. Fegan , F. Feinstein , M. V. Fernandes , A. Fiasson , A. Foerster , G. Fontaine , M. Fussling , S. Gabici , Y. A. Gallant , L. Gerard , D. Gerbig , B. Giebels , J. F. Glicenstein , B. Glueck , P. Goret , D. Goering , D. Hampf , M. Hauser , S. Heinz , G. Heinzelmann , G. Henri , G. Hermann , J. A. Hinton , A. Hoffmann , W. Hofmann , P. Hofverberg , M. Holleran , S. Hoppe , D. Horns , A. Jacholkowska , O. C. de Jager , C. Jahn , I. Jung , K. Katarzynski , U. Katz , S. Kaufmann , M. Kerschhaggl , D. Khangulyan , B. Khelifi , D. Keogh , D. Klochkov , W. Kluzniak , T. Kneiske , Nu. Komin , K. Kosack , R. Kossakowski , G. Lamanna , J. -P. Lenain , T. Lohse , C. -C. Lu , V. Marandon , A. Marcowith , J. Masbou , D. Maurin , T. J. L. McComb , M. C. Medina , J. Mehault , R. Moderski , E. Moulin , M. Naumann-Godo , M. de Naurois , D. Nedbal , D. Nekrassov , N. Nguyen , B. Nicholas , J. Niemiec , S. J. Nolan , S. Ohm , J-F. Olive , E. de Ona Wilhelmi , B. Opitz , K. J. Orford , M. Ostrowski , M. Panter , M. Paz Arribas , G. Pedaletti , G. Pelletier , P. -O. Petrucci , S. Pita , G. Puehlhofer , M. Punch , A. Quirrenbach , B. C. Raubenheimer , M. Raue , S. M. Rayner , 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. Schoeck , A. Schoenwald , U. Schwanke , S. Schwarzburg , S. Schwemmer , A. Shalchi , I. Sushch , M. Sikora , J. L. Skilton , H. Sol , L. Stawarz , R. Steenkamp , C. Stegmann , F. Stinzing , G. Superina , A. Szostek , P. H. Tam , J. -P. Tavernet , R. Terrier , O. Tibolla , M. Tluczykont , K. Valerius , C. van Eldik , G. Vasileiadis , C. Venter , L. Venter , J. P. Vialle , A. Viana , P. Vincent , M. Vivier , H. J. Voelk , F. Volpe , S. Vorobiov , S. J. Wagner , M. Ward , A. A. Zdziarski , A. Zech , H. -S. Zechlin

The Temporal Characteristics of the TeV Gamma-Radiation from Mkn 501 in 1997, I: Data from the Stereoscopic Imaging Atmospheric Cherenkov Telescope System of HEGRA

During 1997, the BL Lac Object Mkn 501 was the brightest known object in the TeV gamma-ray sky. The emission was characterized by dramatic variations in intensity with a mean flux exceeding by a factor of three the steady gamma-ray flux of…

Astrophysics · Physics 2007-05-23 F. Aharonian

A synchrotron self-Compton scenario for the very high energy gamma-ray emission of the radiogalaxy M87

M87 is the first extragalactic source detected in the TeV range that is not a blazar. With the increasing performances of ground-based Cherenkov telescopes, we can now probe the variability in the gamma-ray flux at small timescales, thus…

Astrophysics · Physics 2008-01-14 Jean-Philippe Lenain , Catherine Boisson , Hélène Sol , Krzysztof Katarzynski

Tev Observations of the Variability and Spectrum of Markarian 421

Markarian 421 was the first extragalactic source to be detected with high statistical certainty at TeV energies. The Whipple Observatory gamma-ray telescope has been used to observe the Active Galactic Nucleus, Markarian 421 in 1996 and…

Astrophysics · Physics 2007-05-23 J. E. McEnery , I. H. Bond , P. J. Boyle , S. M. Bradbury , A. C. Breslin , J. H. Buckley , A. M. Burdett , J. Bussons~Gordo , D. A. Carter-Lewis , M. Catanese , M. F. Cawley , D. J . Fegan , J. P. Finley , J. Gaidos , A. Hall , A. M. Hillas , F. Krennrich , R. C. Lamb , R. W. Lessard , C. Masterson , G. Mohanty , P. Moriarty , J. Quinn , A. J. Rodgers , H. J . Rose , F. W. Samuelson , G. H. Sembroski , R. Srinivasan , T. C. Weekes , J. Zweerink

Variability Pattern and the Spectral Evolution of the BL Lacertae Object PKS 2155-304

The TeV blazar PKS 2155-304 was monitored with the X-ray satellite ASCA in 1994 May, as part of a multiwavelength campaign from the radio to X-ray bands. At the beginning of the two-day continuous observation, we detected a large flare,…

Astrophysics · Physics 2009-10-31 J. Kataoka , T. Takahashi , F. Makino , S. Inoue , G. M. Madejski , M. Tashiro , C. M. Urry , H. Kubo

A decade of multi-wavelength observations of the TeV blazar 1ES 1215+303: Extreme shift of the synchrotron peak frequency and long-term optical-gamma-ray flux increase

Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares. With a decade of observations from the Fermi-LAT and…

High Energy Astrophysical Phenomena · Physics 2020-03-23 Janeth Valverde , Deirdre Horan , Denis Bernard , Stephen Fegan , A. U. Abeysekara , A. Archer , W. Benbow , R. Bird , A. Brill , R. Brose , M. Buchovecky , J. H. Buckley , J. L. Christiansen , W. Cui , A. Falcone , Q. Feng , J. P. Finley , L. Fortson , A. Furniss , A. Gent , G. H. Gillanders , C. Giuri , O. Gueta , D. Hanna , T. Hassan , O. Hervet , J. Holder , G. Hughes , T. B. Humensky , P. Kaaret , N. Kelley-Hoskins , M. Kertzman , D. Kieda , M. Krause , F. Krennrich , M. J. Lang , G. Maier , P. Moriarty , R. Mukherjee , D. Nieto , M. Nievas-Rosillo , S. O'Brien , R. A. Ong , A. N. Otte , N. Park , A. Petrashyk , K. Pfrang , A. Pichel , M. Pohl , R. R. Prado , E. Pueschel , J. Quinn , K. Ragan , P. T. Reynolds , D. Ribeiro , G. T. Richards , E. Roache , I. Sadeh , M. Santander , S. S. Scott , G. H. Sembroski , K. Shahinyan , R. Shang , I. Sushch , V. V. Vassiliev , A. Weinstein , R. M. Wells , P. Wilcox , A. Wilhelm , D. A. Williams , T. J Williamson , Giuliana Noto , P. G. Edwards , B. G. Piner , V. Fallah Ramazani , T. Hovatta , J. Jormanainen , E. Lindfors , K. Nilsson , L. Takalo , Y. Y. Kovalev , M. L. Lister , A. B. Pushkarev , T. Savolainen , S. Kiehlmann , W. Max-Moerbeck , A. C. S. Readhead , A. Lähteenmäki , M. Tornikoski

Directional association of TeV to PeV astrophysical neutrinos with radio blazars

Recently we have shown that high-energy neutrinos above 200 TeV detected by IceCube are produced within several parsecs in the central regions of radio-bright blazars, that is active galactic nuclei with jets pointing towards us. To…

High Energy Astrophysical Phenomena · Physics 2021-02-22 A. V. Plavin , Y. Y. Kovalev , Y. A. Kovalev , S. V. Troitsky

Imaging Atmospheric Cerenkov Telescopes: Techniques and Results

The hunt for cosmic TeV particle accelerators is prospering through Imaging Atmospheric Cerenkov Telescopes. We face challenges such as low light levels and MHz trigger rates, and the need to distinguish between particle air showers…

Astrophysics · Physics 2007-05-23 S. M. Bradbury

Relativistic electron beams in IDV blazars

The observed variability of BL Lac objects and Quasars on timescales <1 day (intraday variability, IDV) have revealed radio brightness temperatures up to 10^{16}-10^{20} K. These values challenge the beaming model with isotropic comoving…

Astrophysics · Physics 2007-05-23 A. R. Crusius-W"atzel , H. Lesch

The variability patterns of the TeV blazar PG 1553+113 from a decade of MAGIC and multi-band observations

PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying…

High Energy Astrophysical Phenomena · Physics 2024-03-13 MAGIC Collaboration , H. Abe , S. Abe , J. Abhir , V. A. Acciari , I. Agudo , T. Aniello , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , C. Arcaro , M. Artero , K. Asano , D. Baack , A. Babić , A. Baquero , U. Barres de Almeida , I. Batković , J. Baxter , J. Becerra González , E. Bernardini , J. Bernete , A. Berti , J. Besenrieder , C. Bigongiari , A. Biland , O. Blanch , G. Bonnoli , Ž. Bošnjak , I. Burelli , G. Busetto , A. Campoy-Ordaz , A. Carosi , R. Carosi , M. Carretero-Castrillo , A. J. Castro-Tirado , Y. Chai , A. Cifuentes , S. Cikota , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , G. D'Amico , V. D'Elia , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , A. Del Popolo , M. Delfino , J. Delgado , C. Delgado Mendez , D. Depaoli , F. Di Pierro , L. Di Venere , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , D. Elsaesser , G. Emery , J. Escudero , L. Fariña , A. Fattorini , L. Foffano , L. Font , S. Fukami , Y. Fukazawa , R. J. García López , S. Gasparyan , M. Gaug , J. G. Giesbrecht Paiva , N. Giglietto , F. Giordano , P. Gliwny , R. Grau , J. G. Green , D. Hadasch , A. Hahn , L. Heckmann , J. Herrera , T. Hovatta , D. Hrupec , M. Hütten , R. Imazawa , T. Inada , R. Iotov , K. Ishio , I. Jiménez Martínez , J. Jormanainen , D. Kerszberg , G. W. Kluge , Y. Kobayashi , P. M. Kouch , H. Kubo , J. Kushida , M. Láinez Lezáun , A. Lamastra , F. Leone , E. Lindfors , I. Liodakis , S. Lombardi , F. Longo , M. López-Moya , A. López-Oramas , S. Loporchio , A. Lorini , B. Machado de Oliveira Fraga , P. Majumdar , M. Makariev , G. Maneva , N. Mang , M. Manganaro , K. Mannheim , M. Mariotti , M. Martínez , M. Martínez-Chicharro , A. Mas-Aguilar , D. Mazin , S. Menchiari , S. Mender , D. Miceli , T. Miener , J. M. Miranda , R. Mirzoyan , M. Molero González , E. Molina , H. A. Mondal , A. Moralejo , D. Morcuende , T. Nakamori , C. Nanci , V. Neustroev , C. Nigro , L. Nikolić , K. Nilsson , K. Nishijima , T. Njoh Ekoume , K. Noda , S. Nozaki , Y. Ohtani , A. Okumura , J. Otero-Santos , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , D. Pavlović , M. Persic , M. Pihet , G. Pirola , F. Podobnik , P. G. Prada Moroni , E. Prandini , G. Principe , C. Priyadarshi , W. Rhode , M. Ribó , J. Rico , C. Righi , N. Sahakyan , T. Saito , K. Satalecka , F. G. Saturni , B. Schleicher , K. Schmidt , F. Schmuckermaier , J. L. Schubert , T. Schweizer , A. Sciaccaluga , J. Sitarek , A. Spolon , A. Stamerra , J. Strišković , D. Strom , Y. Suda , S. Suutarinen , H. Tajima , R. Takeishi , F. Tavecchio , P. Temnikov , K. Terauchi , T. Terzić , M. Teshima , L. Tosti , S. Truzzi , A. Tutone , S. Ubach , J. van Scherpenberg , S. Ventura , V. Verguilov , I. Viale , C. F. Vigorito , V. Vitale , R. Walter , C. Wunderlich , T. Yamamoto , MWL collaborators , : , H. Jermak , I. A. Steele , P. S. Smith , D. Blinov , C. M. Raiteri , M. Villata , D. O. Mirzaqulov , S. O. Kurtanidze , D. Carosati , S. S. Savchenko , J. A. Acosta-Pulido , G. A. Borman , V. Bozhilov , M. I. Carnerero , R. A. Chigladze , G. Damljanovic , S. A. Ehgamberdiev , M. Feige , T. S. Grishina , A. C. Gupta , V. A. Hagen-Thorn , S. Ibryamov , R. Z. Ivanidze , S. G. Jorstad , J. Kania , G. N. Kimeridze , E. N. Kopatskaya , M. Kopp , L. Kunkel , O. M. Kurtanidze , V. M. Larionov , E. G. Larionova , L. V. Larionova , C. Lorey , A. Marchini , A. P. Marscher , M. Minev , D. A. Morozova , M. G. Nikolashvili , E. Ovcharov , D. Reinhart , A. C. Sadun , A. Scherbantin , L. Schneider , E. Semkov , L. A. Sigua , R. Steineke , Yu. V. Troitskaya , I. S. Troitskiy , A. Valcheva , A. A. Vasilyev , O. Vince , E. Zaharieva , N. Zottmann , S. Kiehlmann , A. Readhead , W. Max-Moerbeck , R. A. Reeves , A. Sandrinelli , V. Fallah Ramazani , M. Giroletti , S. Righini , N. Marchili , B. Patricelli , G. Ghirlanda , R. Lico

Short time scale variability at gamma rays in FSRQs and implications on the current models

We studied the rapid variability at GeV gamma rays of the flat-spectrum radio quasar PKS 1222+216, which was recently found by the MAGIC Cerenkov telescope to display very short variability (minutes time scale) at hundreds of GeV. We…

High Energy Astrophysical Phenomena · Physics 2012-02-14 L. Foschini , G. Ghisellini , F. Tavecchio , G. Bonnoli , A. Stamerra

Characterizing X-ray Variability of TeV Blazars

In this review, I will discuss how to characterize synchrotron X-ray variability of TeV blazars by using the observed/simulated light curves. Apparently, temporal studies provide independent and complementary information to the spectral…

Astrophysics · Physics 2008-06-27 Jun Kataoka

Diffuse emission from stochastic sources

Diffuse emission in gamma-rays and neutrinos are produced by the interaction of cosmic rays with the interstellar medium. Below some hundreds of TeV, the sources of these cosmic rays are most likely Galactic. Hence, observations of…

High Energy Astrophysical Phenomena · Physics 2025-09-25 Anton Stall , Philipp Mertsch

X-ray Intraday Variability of Five TeV Blazars with NuSTAR

We have examined 40 NuSTAR light curves (LCs) of five TeV emitting high synchrotron peaked blazars: 1ES 0229+200, Mrk 421, Mrk 501, 1ES 1959+650 and PKS 2155-304. Four of the blazars showed intraday variability in the NuSTAR energy range of…

High Energy Astrophysical Phenomena · Physics 2017-12-20 Ashwani Pandey , Alok C. Gupta , Paul J. Wiita

On the prospects of gamma-ray burst detection in the TeV band

A gamma-ray burst (GRB) jet running into an external medium is expected to generate luminous GeV-TeV emission lasting from minutes to several hours. The high-energy emission results from inverse Compton upscattering of prompt and afterglow…

High Energy Astrophysical Phenomena · Physics 2017-09-20 Indrek Vurm , Andrei M. Beloborodov

New Multiwavelength Observations of PKS 2155-304 and Implications for the Coordinated Variability Patterns of Blazars

The TeV blazar PKS 2155--304 was the subject of an intensive 2 week optical and near-infrared observing campaign in 2004 August with the CTIO 0.9m telescope. During this time, simultaneous X-ray data from RXTE were also obtained. We compare…

Astrophysics · Physics 2009-11-13 M. Angela Osterman , H. Richard Miller , Kevin Marshall , Wesley T. Ryle , Hugh Aller , Margo Aller , John P. McFarland

TEV GAMMA-RAYS FROM PROTON BLAZARS

Proton acceleration in nearby blazars can be diagnosed measuring their intense TeV $\gamma$-ray emission. Flux predictions for 1101+384 (Mrk421) and 1219+285 (ON231), both strong EGRET sources (0.1-10 GeV), are obtained from model spectra…

Astrophysics · Physics 2009-10-28 Karl Mannheim

Discovery of a high confidence soft lag from an X-ray flare of Markarian 421

We present the X-ray variability properties of the X-ray and TeV bright blazar Mrk 421 with a ~60 ks long XMM-Newton observation performed on November 9-10, 2005. The source experienced a pronounced flare, of which the inter-band time lags…

High Energy Astrophysical Phenomena · Physics 2010-03-29 You-Hong Zhang , Zheng-Tian Hou , Li Shao , Peng Zhang