Related papers: Multi-wavelength Observations of VHE BL Lac Object…

Discovery of very high energy gamma-ray emission from the low-frequency peaked BL Lacertae object BL Lacertae

The MAGIC collaboration observed BL Lacertae for 22.2 hr during 2005 August to December and for 26 hr during 2006 July to September. The source is the historical prototype and eponym of a class of low-frequency peaked BL Lacertae (LBL)…

Astrophysics · Physics 2009-11-13 MAGIC Collaboration , J. Albert

5.5 years multi-wavelength variability of Mrk 421: evidences of leptonic emission from the radio to TeV

Mrk 421 is a high-synchrotron-peaked blazar featuring bright and persistent GeV and TeV emission. We use the longest and densest ongoing unbiased observing campaign obtained at TeV and GeV energies during 5.5 years with the FACT telescope…

High Energy Astrophysical Phenomena · Physics 2019-10-01 Vitalii Sliusar , Axel Arbet-Engels , Dominik Baack , Matteo Balbo , Marvin Beck , Adrian Biland , Michael Blank , Thomas Bretz , Kai Bruegge , Michael Bulinski , Jens Buss , Manuel Doerr , Daniela Dorner , Dominik Elsaesser , Dorothee Hildebrand , Roman Iotov , Marc Klinger , Karl Mannheim , Dominik Neise , Maximilian Noethe , Aleksander Paravac , Wolfgang Rhode , Bernd Schleicher , Kevin Sedlaczek , Amit Shukla , Laurits Tani , Fabian Theissen , Roland Walter

Studying flux variability of the BL Lac object 1ES0806+524 with MAGIC in a multi-wavelength context

We present results of multi-wavelength (MWL) observations of the high-frequency-peaked BL Lacertae (HBL) object 1ES 0806+524 (z=0.138). Triggered by a high optical state, very high energy (VHE; E > 100 GeV) observations were carried out…

High Energy Astrophysical Phenomena · Physics 2019-08-15 K. Berger , C. Schultz , E. Lindfors R. Rheinthal , A. Stamerra , F. Tavecchio , S. Buson , F. D'Ammando , T. Hovatta

Simultaneous observations of PKS 2155-304 with H.E.S.S., Fermi, RXTE and ATOM: spectral energy distributions and variability in a low state

We report on the first simultaneous observations that cover the optical, X-ray, and high energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 25 August and 6 September 2008,…

High Energy Astrophysical Phenomena · Physics 2009-07-22 H. E. S. S. , Fermi-LAT collaborations

On the TeV gamma-ray and X-ray correlations exhibited in high-energy peaked BL Lacs: Mrk 501 and 1ES 1959+650

The spectral energy distribution (SED) of blazars is generally understood through the standard one-zone synchrotron self-Compton (SSC) model, where a strong correlation between X-ray and TeV gamma-ray fluxes is expected. Recently, for Mrk…

High Energy Astrophysical Phenomena · Physics 2019-09-04 Mabel Osorio , Rodrigo Sacahui , M. Magdalena González , Nissim Fraija , José Andrés García-González

Multiwavelength observations of a TeV-Flare from W Com

We report results from an intensive campaign of multiwavelength observations of the intermediate-frequency-peaked BL Lacertae object W Com (z=0.102) during a strong outburst of very high energy (VHE; E > 180 GeV) gamma-ray emission in June…

High Energy Astrophysical Phenomena · Physics 2009-07-24 G. Maier , E. Pian

Very Long Baseline polarimetry and the gamma-ray connection in Markarian 421 during the broadband campaign in 2011

We analyzed data in polarized intensity obtained with the Very Long Baseline Array (VLBA) at twelve epochs (one observation per month from January to December 2011) at 15, 24, and 43 GHz. For the absolute orientation of the electric vector…

High Energy Astrophysical Phenomena · Physics 2014-11-11 R. Lico , M. Giroletti , M. Orienti , G. Giovannini , J. L. Gomez , C. Casadio , F. D'Ammando , M. G. Blasi , W. Cotton , P. G. Edwards , L. Fuhrmann , S. Jorstad , M. Kino , Y. Y. Kovalev , T. P. Krichbaum , A. P. Marscher , D. Paneque , G. Piner , K. Sokolovsky

Markarian 501 in X-ray bright state - RXTE observations

Mrk 501 has been in a state of very high flux in X-rays and VHE gamma-rays during 1997. In July 1997 near its hitherto maximum X-ray brightness intense multifrequency observations of Mrk 501 have been performed at radio, near infrared,…

Astrophysics · Physics 2016-08-30 G. Lamer , S. J. Wagner

Four Years of Extreme Ultraviolet Observations of Markarian 421. I: Spectral Analysis

We analyzed the ~950 ks of spectroscopic data accumulated by the Extreme Ultraviolet Explorer (EUVE) satellite between 1994 and 1997 for the BL Lacertae object Markarian 421. The EUV spectrum is well detected in the 70-110 A (112-177 eV)…

Astrophysics · Physics 2009-10-31 Ilaria Cagnoni , Antonella Fruscione

Five-year Monitorings of TeV Blazars with ASCA and RXTE

We study the temporal/spectral variability of two extragalactic TeV sources, Mrk 421 and Mrk 501, based on 5-year observations with the ASCA and RXTE satellites. We found that the peak of the synchrotron emission exists just in the X-ray…

Astrophysics · Physics 2007-05-23 J. Kataoka , T. Takahashi , F. Takahara , P. G. Edwards , K. Hayashida , S. Inoue , N. Iyomoto , N. Kawai , G. M. Madejski , C. Tanihata , S. J. Wagner

Multi-wavelength observations of PKS 2155-304 with H.E.S.S

The High Energy Stereoscopic System (H.E.S.S.) has observed the high-frequency peaked BL Lac object PKS2155-304 in 2003 between October 19 and November 26 in Very High Energy (VHE) gamma-rays (E>160 GeV for these observations). Observations…

Astrophysics · Physics 2012-08-27 H. E. S. S. Collaboration , : , Aharonian

Temporary EHBL-like behavior of Markarian 501 during July 2014 VHE flaring

Markarian 501, a BL Lac object well-known as a high energy gamma-ray source, has exhibited several epochs of very high energy (VHE) gamma-ray flaring events when its synchrotron peak frequency shifted above $10^{17}$ Hz, a signature of…

High Energy Astrophysical Phenomena · Physics 2026-04-08 Sarira Sahu , A. U. Puga Oliveros , D. I. Páez-Sánchez , G. Sánchez-Colón , Subhash Rajpoot , M. E. Iglesias Martínez , José Guerra Carmenate , P. Fernández de Córdoba , Gaetano Lambiase

Mkn 421 was observed for about two days with BeppoSAX, prior to and partly overlapping the start of a 1 week continuous exposure with ASCA in April 1998, as part of a world-wide multiwavelength campaign. A pronounced, well defined, flare…

Astrophysics · Physics 2009-10-31 L. Maraschi , G. Fossati , F. Tavecchio , L. Chiappetti , A. Celotti , G. Ghisellini , P. Grandi , E. Pian , G. Tagliaferri , A. Treves , A. C. Breslin , J. H. Buckley , D. A. Carter-Lewis , M. Catanese , M. F. Cawley , D. J. Fegan , S. Fegan , J. Finley , J. Gaidos , T. Hall , A. M. Hillas , F. Krennrich , R. W. Lessard , C. Masterson , P. Moriarty , J. Quinn , J. Rose , F. Samuelson , T. C. Weekes , T. C. Weekes

Discovery of Very High-Energy Gamma-Ray Radiation from the BL Lac 1ES 0806+524

The high-frequency-peaked BL-Lacertae object \objectname{1ES 0806+524}, at redshift z=0.138, was observed in the very-high-energy (VHE) gamma-ray regime by VERITAS between November 2006 and April 2008. These data encompass the two-, and…

Astrophysics · Physics 2015-05-13 VERITAS Collaboration , V. Acciari , E. Aliu , T. Arlen , M. Bautista , M. Beilicke , W. Benbow , M. Böttcher , S. M. Bradbury , J. H. Buckley , V. Bugaev , Y. Butt , K. Byrum , A. Cannon , O. Celik , A. Cesarini , Y. C. Chow , L. Ciupik , P. Cogan , P. Colin , W. Cui , R. Dickherber , C. Duke , T. Ergin , A. Falcone , S. J. Fegan , J. P. Finley , G. Finnegan , P. Fortin , L. Fortson , A. Furniss , D. Gall , K. Gibbs , G. H. Gillanders , J. Grube , R. Guenette , G. Gyuk , D. Hanna , E. Hays , J. Holder , D. Horan , C. M. Hui , T. B. Humensky , A. Imran , P. Kaaret , N. Karlsson , M. Kertzman , D. Kieda , J. Kildea , A. Konopelko , H. Krawczynski , F. Krennrich , M. J. Lang , S. LeBohec , G. Maier , A. McCann , M. McCutcheon , J. Millis , P. Moriarty , R. Mukherjee , T. Nagai , R. A. Ong , A. N. Otte , D. Pandel , J. S. Perkins , D. Petry , M. Pohl , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , E. Roache , J. Rose , M. Schroedter , G. H. Sembroski , A. W. Smith , D. Steele , S. P. Swordy , M. Theiling , J. A. Toner , L. Valcarcel , A. Varlotta , V. V. Vassiliev , R. G. Wagner , S. P. Wakely , J. E. Ward , T. C. Weekes , A. Weinstein , R. J. White , D. A. Williams , S. Wissel , M. Wood , B. Zitzer

A search for VHE counterparts of galactic Fermi sources

Very high-energy (VHE; E > 100 GeV) gamma-rays have been detected from a wide range of astronomical objects, such as SNRs, pulsars and pulsar wind nebulae, AGN, gamma-ray binaries, molecular clouds, and possibly star-forming regions as…

High Energy Astrophysical Phenomena · Physics 2010-01-19 P. H. Thomas Tam , Stefan Wagner , Omar Tibolla , Ryan Chaves

A search for spectral hysteresis and energy-dependent time lags from X-ray and TeV gamma-ray observations of Mrk 421

Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars simultaneously at different wavelengths, especially in the X-ray and gamma-ray…

High Energy Astrophysical Phenomena · Physics 2016-12-28 A. U. Abeysekara , S. Archambault , A. Archer , W. Benbow , R. Bird , M. Buchovecky , J. H. Buckley , V. Bugaev , J. V Cardenzana , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , J. D. Eisch , A. Falcone , Q. Feng , J. P. Finley , H. Fleischhack , A. Flinders , L. Fortson , A. Furniss , S. Griffin , M. Hütten , N. Håkansson , D. Hanna , O. Hervet , J. Holder , T. B. Humensky , P. Kaaret , P. Kar , M. Kertzman , D. Kieda , M. Krause , S. Kumar , M. J. Lang , G. Maier , S. McArthur , A. McCann , K. Meagher , P. Moriarty , R. Mukherjee , D. Nieto , S. O'Brien , R. A. Ong , A. N. Otte , N. Park , V. Pelassa , M. Pohl , A. Popkow , E. Pueschel , K. Ragan , P. T. Reynolds , G. T. Richards , E. Roache , I. Sadeh , M. Santander , G. H. Sembroski , K. Shahinyan , D. Staszak , I. Telezhinsky , J. V. Tucci , J. Tyler , S. P. Wakely , A. Weinstein , A. Wilhelm , D. A. Williams , M. L. Ahnen , S. Ansoldi , L. A. Antonelli , P. Antoranz , C. Arcaro , A. Babic , B. Banerjee , P. Bangale , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , E. Bernardini , A. Berti , B. Biasuzzi , A. Biland , O. Blanch , S. Bonnefoy , G. Bonnoli , F. Borracci , T. Bretz , R. Carosi , A. Carosi , A. Chatterjee , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Cumani , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , E. de Oña Wilhelmi , F. Di Pierro , M. Doert , A. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Eisenacher Glawion , D. Elsaesser , M. Engelkemeier , V. Fallah Ramazani , A. Fernández-Barral , D. Fidalgo , M. V. Fonseca , L. Font , C. Fruck , D. Galindo , R. J. García López , M. Garczarczyk , M. Gaug , P. Giammaria , N. Godinović , D. Gora , D. Guberman , D. Hadasch , A. Hahn , T. Hassan , M. Hayashida , J. Herrera , J. Hose , D. Hrupec , G. Hughes , W. Idec , K. Kodani , Y. Konno , H. Kubo , J. Kushida , D. Lelas , E. Lindfors , S. Lombardi , F. Longo , M. López , R. López-Coto , P. Majumdar , M. Makariev , K. Mallot , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , B. Marcote , M. Mariotti , M. Martínez , D. Mazin , U. Menzel , R. Mirzoyan , A. Moralejo , E. Moretti , D. Nakajima , V. Neustroev , A. Niedzwiecki , M. Nievas Rosillo , K. Nilsson , K. Nishijima , K. Noda , L. Nogués , M. Nöthe , S. Paiano , J. Palacio , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , X. Paredes-Fortuny , G. Pedaletti , M. Peresano , L. Perri , M. Persic , J. Poutanen , P. G. Prada Moroni , E. Prandini , I. Puljak , J. R. Garcia , I. Reichardt , W. Rhode , M. Ribó , J. Rico , T. Saito , K. Satalecka , S. Schroeder , T. Schweizer , S. N. Shore , A. Sillanpää , J. Sitarek , I. Snidaric , D. Sobczynska , A. Stamerra , M. Strzys , T. Surić , L. Takalo , F. Tavecchio , P. Temnikov , T. Terzić , D. Tescaro , M. Teshima , D. F. Torres , N. Torres-Albà , T. Toyama , A. Treves , G. Vanzo , M. Vazquez Acosta , I. Vovk , J. E. Ward , M. Will , M. H. Wu , R. Zanin , T. Hovatta , I. de la Calle Perez , P. S. Smith , E. Racero , M. Baloković

VHE $\gamma$-ray discovery and multi-wavelength study of the blazar 1ES 2322-409

A hotspot at a position compatible with the BL Lac object 1ES 2322-409 was serendipitously detected with H.E.S.S. during observations performed in 2004 and 2006 on the blazar PKS 2316-423. Additional data on 1ES 2322-409 were taken in 2011…

High Energy Astrophysical Phenomena · Physics 2018-10-17 H. E. S. S. Collaboration , : , H. Abdalla , F. Aharonian , F. Ait Benkhali , E. O. Angüner , M. Arakawa , C. Arcaro , C. Armand , M. Arrieta , M. Backes , M. Barnard , Y. Becherini , J. Becker Tjus , D. Berge , S. Bernhard , K. Bernlöhr , R. Blackwell , M. Böttcher , C. Boisson , J. Bolmont , S. Bonnefoy , P. Bordas , J. Bregeon , F. Brun , P. Brun , M. Bryan , M. Büchele , T. Bulik , T. Bylund , M. Capasso , S. Caroff , A. Carosi , S. Casanova , M. Cerruti , N. Chakraborty , S. Chandra , R. C. G. Chaves , A. Chen , S. Colafrancesco , B. Condon , I. D. Davids , C. Deil , J. Devin , P. deWilt , L. Dirson , A. Djannati-Ataï , A. Dmytriiev , A. Donath , L. O'C. Drury , J. Dyks , K. Egberts , G. Emery , J. -P. Ernenwein , S. Eschbach , S. Fegan , A. Fiasson , G. Fontaine , S. Funk , M. Füßling , S. Gabici , Y. A. Gallant , T. Garrigoux , F. Gaté , G. Giavitto , D. Glawion , J. F. Glicenstein , D. Gottschall , M. -H. Grondin , J. Hahn , M. Haupt , G. Heinzelmann , G. Henri , G. Hermann , J. A. Hinton , W. Hofmann , C. Hoischen , T. L. Holch , M. Holler , D. Horns , D. Huber , H. Iwasaki , A. Jacholkowska , M. Jamrozy , D. Jankowsky , F. Jankowsky , L. Jouvin , I. Jung-Richardt , M. A. Kastendieck , K. Katarzyński , M. Katsuragawa , U. Katz , D. Kerszberg , D. Khangulyan , B. Khélifi , J. King , S. Klepser , W. Kluźniak , Nu. Komin , K. Kosack , S. Krakau , M. Kraus , P. P. Krüger , G. Lamanna , J. Lau , J. Lefaucheur , A. Lemière , M. Lemoine-Goumard , J. -P. Lenain , E. Leser , T. Lohse , M. Lorentz , R. López-Coto , I. Lypova , D. Malyshev , V. Marandon , A. Marcowith , C. Mariaud , G. Guillem Martí-Devesa , R. Marx , G. Maurin , P. J. Meintjes , A. M. W. Mitchell , R. Moderski , M. Mohamed , L. Mohrmann , E. Moulin , T. Murach , S. Nakashima , M. de Naurois , H. Ndiyavala , F. Niederwanger , J. Niemiec , L. Oakes , P. O'Brien , H. Odaka , S. Ohm , M. Ostrowski , I. Oya , M. Padovani , M. Panter , R. D. Parsons , C. Perennes , P. -O. Petrucci , B. Peyaud , Q. Piel , S. Pita , V. Poireau , A. Priyana Noel , D. A. Prokhorov , H. Prokoph , G. Pühlhofer , M. Punch , A. Quirrenbach , S. Raab , R. Rauth , A. Reimer , O. Reimer , M. Renaud , F. Rieger , L. Rinchiuso , C. Romoli , G. Rowell , B. Rudak , E. Ruiz-Velasco , V. Sahakian , S. Saito , D. A. Sanchez , A. Santangelo , M. Sasaki , R. Schlickeiser , F. Schüssler , A. Schulz , U. Schwanke , S. Schwemmer , M. Seglar-Arroyo , M. Senniappan , A. S. Seyffert , N. Shafi , I. Shilon , K. Shiningayamwe , R. Simoni , A. Sinha , H. Sol , F. Spanier , A. Specovius , M. Spir-Jacob , Ł. Stawarz , R. Steenkamp , C. Stegmann , C. Steppa , I. Sushch , T. Takahashi , J. -P. Tavernet , T. Tavernier , A. M. Taylor , R. Terrier , L. Tibaldo , D. Tiziani , M. Tluczykont , C. Trichard , M. Tsirou , N. Tsuji , R. Tuffs , Y. Uchiyama , D. J. van der Walt , C. van Eldik , C. van Rensburg , B. van Soelen , G. Vasileiadis , J. Veh , C. Venter , A. Viana , P. Vincent , J. Vink , F. Voisin , H. J. Völk , T. Vuillaume , Z. Wadiasingh , S. J. Wagner , P. Wagner , R. M. Wagner , R. White , A. Wierzcholska , A. Wörnlein , R. Yang , D. Zaborov , M. Zacharias , R. Zanin , A. A. Zdziarski , A. Zech , F. Zefi , A. Ziegler , J. Zorn , N. Żywucka

Multi-wavelength Observations of Markarian 501

The very high energy (VHE; E > 100 GeV) gamma-ray blazar Markarian 501 has a history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. A short term…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Daniel Gall

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

Dissecting the long-term emission behaviour of the BL Lac object Mrk 421

We report on long-term multi-wavelength monitoring of blazar Mrk 421 by the GASP-WEBT collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007-2015, characterized by…

High Energy Astrophysical Phenomena · Physics 2019-08-14 M. I. Carnerero , C. M. Raiteri , M. Villata , J. A. Acosta-Pulido , V. M. Larionov , P. S. Smith , F. D'Ammando