Related papers: VHE gamma-ray emission of PKS 2155-304: spectral a…

Multi-wavelength characterization of the blazar S5~0716+714 during an unprecedented outburst phase

The BL Lac object S5~0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in…

High Energy Astrophysical Phenomena · Physics 2020-01-29 MAGIC Collaboration , M. L. Ahnen , S. Ansoldi , L. A. Antonelli , C. Arcaro , D. Baack , A. Babić , B. Banerjee , P. Bangale , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , E. Bernardini , R. Ch. Berse , A. Berti , W. Bhattacharyya , A. Biland , O. Blanch , G. Bonnoli , R. Carosi , A. Carosi , G. Ceribella , A. Chatterjee , S. M. Colak , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Cumani , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , M. Delfino , J. Delgado , F. Di Pierro , A. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Elsaesser , V. Fallah Ramazani , A. Fernández-Barral , D. Fidalgo , M. V. Fonseca , L. Font , C. Fruck , D. Galindo , S. Gallozzi , 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 , K. Ishio , Y. Konno , H. Kubo , J. Kushida , D. Kuveždić , D. Lelas , E. Lindfors , S. Lombardi , F. Longo , M. López , C. Maggio , P. Majumdar , M. Makariev , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , M. Mariotti , M. Martínez , S. Masuda , D. Mazin , K. Mielke , M. Minev , J. M. Miranda , R. Mirzoyan , A. Moralejo , V. Moreno , E. Moretti , T. Nagayoshi , 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 , M. Peresano , M. Persic , P. G. Prada Moroni , E. Prandini , I. Puljak , J. R. Garcia , I. Reichardt , W. Rhode , M. Ribó , J. Rico , C. Righi , A. Rugliancich , T. Saito , K. Satalecka , T. Schweizer , J. Sitarek , I. Šnidarić , D. Sobczynska , A. Stamerra , M. Strzys , T. Surić , M. Takahashi , L. Takalo , F. Tavecchio , P. Temnikov , T. Terzić , M. Teshima , N. Torres-Albà , A. Treves , S. Tsujimoto , G. Vanzo , M. Vazquez Acosta , I. Vovk , J. E. Ward , M. Will , D. Zarić , Fermi-LAT Collaboration , D. Bastieri , D. Gasparrini , B. Lott , B. Rani , D. J. Thompson , MWL Collaborators , I. Agudo , E. Angelakis , G. A. Borman , C. Casadio , T. S. Grishina , M. Gurwell , T. Hovatta , R. Itoh , E. Järvelä , H. Jermak , S. Jorstad , E. N. Kopatskaya , A. Kraus , T. P. Krichbaum , N. P. M. Kuin , A. Lähteenmäki , V. M. Larionov , L. V. Larionova , A. Y. Lien , G. Madejski , A. Marscher , I. Myserlis , W. Max-Moerbeck , S. N. Molina , D. A. Morozova , K. Nalewajko , T. J. Pearson , V. Ramakrishnan , A. C. S. Readhead , R. A. Reeves , S. S. Savchenko , I. A. Steele , M. Tornikoski , Yu. V. Troitskaya , I. Troitsky , A. A. Vasilyev , J. Anton Zensus

Variability and Spectral Characteristics of Three Flaring Gamma-ray Quasars Observed by VERITAS and Fermi-LAT

Flat spectrum radio quasars (FSRQs) are the most luminous blazars at GeV energies, but only rarely emit detectable fluxes of TeV gamma rays, typically during bright GeV flares. We explore the gamma-ray variability and spectral…

High Energy Astrophysical Phenomena · Physics 2022-01-26 C. B. Adams , J. Batshoun , W. Benbow , A. Brill , J. H. Buckley , M. Capasso , B. Cavins , J. L. Christiansen , P. Coppi , M. Errando , K. A Farrell , Q. Feng , J. P. Finley , G. M. Foote , L. Fortson , A. Furniss , A. Gent , C. Giuri , D. Hanna , T. Hassan , O. Hervet , J. Holder , M. Houck , T. B. Humensky , W. Jin , P. Kaaret , M. Kertzman , D. Kieda , F. Krennrich , S. Kumar , M. Lundy , G. Maier , C. E McGrath , P. Moriarty , R. Mukherjee , D. Nieto , M. Nievas-Rosillo , S. O'Brien , R. A. Ong , A. Oppenheimer , A. N. Otte , S. Patel , K. Pfrang , M. Pohl , R. R. Prado , E. Pueschel , J. Quinn , K. Ragan , P. T. Reynolds , A. Rhatigan , D. Ribeiro , E. Roache , J. L. Ryan , M. Santander , G. H. Sembroski , D. A. Williams , T. J Williamson , J. Valverde , D. Horan , S. Buson , C. C. Cheung , S. Ciprini , D. Gasparrini , R. Ojha , P. van Zyl , L. Sironi

Bimodal radio variability in OVRO-40m-monitored blazars

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

Exploring Short-Term Optical Variability of Blazars Using $\textit{TESS}$

We present a first systematic time series study of a sample of blazars observed by the Transiting Exoplanet Survey Satellite $\textit{TESS}$ spacecraft. By cross matching the positions of the sources in the TESS observations with those from…

High Energy Astrophysical Phenomena · Physics 2022-11-23 Vivek Reddy Pininti , Gopal Bhatta , Sagarika Paul , Aman Kumar , Aayushi Rajgor , Rahul Barnwal , Sarvesh Gharat

Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240

We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides…

High Energy Astrophysical Phenomena · Physics 2015-06-19 S. Archambault , T. Aune , B. Behera , M. Beilicke , W. Benbow , K. Berger , R. Bird , J. Biteau , V. Bugaev , K. Byrum , J. V Cardenzana , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , J. Dumm , M. Errando , A. Falcone , S. Federici , Q. Feng , J. P. Finley , H. Fleischhack , L. Fortson , A. Furniss , N. Galante , G. H. Gillanders , S. Griffin , S. T. Griffiths , J. Grube , G. Gyuk , D. Hanna , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , M. Kertzman , Y. Khassen , D. Kieda , H. Krawczynski , F. Krennrich , S. Kumar , M. J. Lang , A. S Madhavan , G. Maier , A. McCann , K. Meagher , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faolain de Bhroithe , R. A. Ong , A. N. Otte , N. Park , M. Pohl , A. Popkow , H. Prokoph , J. Quinn , K. Ragan , J. Rajotte , L. C. Reyes , P. T. Reynolds , G. T. Richards , E. Roache , G. H. Sembroski , K. Shahinyan , D. Staszak , I. Telezhinsky , J. V. Tucci , J. Tyler , A. Varlotta , V. V. Vassiliev , S. Vincent , S. P. Wakely , A. Weinstein , R. Welsing , A. Wilhelm , D. A. Williams , M. Ackermann , M. Ajello , A. Albert , L. Baldini , D. Bastieri , R. Bellazzini , E. Bissaldi , J. Bregeon , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , P. A. Caraveo , E. Cavazzuti , E. Charles , J. Chiang , S. Ciprini , R. Claus , S. Cutini , F. D'Ammando , A. de Angelis , F. de Palma , C. D. Dermer , S. W. Digel , L. Di Venere , P. S. Drell , C. Favuzzi , A. Franckowiak , P. Fusco , F. Gargano , D. Gasparrini , N. Giglietto , F. Giordano , M. Giroletti , I. A. Grenier , S. Guiriec , T. Jogler , M. Kuss , S. Larsson , L. Latronico , F. Longo , F. Loparco , P. Lubrano , G. M. Madejski , M. Mayer , M. N. Mazziotta , P. F. Michelson , T. Mizuno , M. E. Monzani , A. Morselli , S. Murgia , E. Nuss , T. Ohsugi , J. F. Ormes , J. S. Perkins , F. Piron , G. Pivato , S. Raino , M. Razzano , A. Reimer , O. Reimer , S. Ritz , M. Schaal , C. Sgro , E. J. Siskind , P. Spinelli , H. Takahashi , L. Tibaldo , M. Tinivella , E. Troja , G. Vianello , M. Werner , M. Wood

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

Temporal and spectral study of PKS 0208-512 during the 2019-2020 flare

We present the temporal and spectral study of blazar PKS 0208-512, using recent flaring activity from November 2019 to May 2020, as detected by the Fermi-LAT observatory. The contemporaneous X-ray, optical/UV observations from…

High Energy Astrophysical Phenomena · Physics 2022-07-12 Rukaiya Khatoon , Raj Prince , Zahir Shah , Sunder Sahayanathan , Rupjyoti Gogoi

HESS Observations and VLT Spectroscopy of PG 1553+113

AIMS: The properties of the very high energy (VHE; E>100 GeV) gamma-ray emission from the high-frequency peaked BL Lac PG 1553+113 are investigated. An attempt is made to measure the currently unknown redshift of this object. METHODS: VHE…

Astrophysics · Physics 2011-02-11 HESS Collaboration , F. Aharonian

Characteristic X-ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine

We have studied the rapid X-ray variability of three extragalactic TeV gamma-ray sources; Mrk 421, Mrk 501 and PKS 2155-304. Analyzing the X-ray light curves obtained from ASCA and/or RXTE observations between 1993 and 1998, we have…

Astrophysics · Physics 2009-11-06 Jun Kataoka , Tadayuki Takahashi , Stefan J. Wagner , Naoko Iyomoto , Philip G. Edwards , Kiyoshi Hayashida , Susumu Inoue , Greg M. Madejski , Fumio Takahara , Chiharu Tanihata , Nobuyuki Kawai

Short-term X-ray Variability during Different Activity Phases of Blazars S5 0716+714 and PKS 2155-304

We explored the statistical properties of short-term X-ray variability using long-exposure {\it XMM-Newton} data during high X-ray variability phases of blazars S5 0716+714 and PKS 2155-304. In general, hardness ratio shows correlated…

High Energy Astrophysical Phenomena · Physics 2020-09-15 Pankaj Kushwaha , Main Pal

VERITAS detection of $\gamma$-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations

During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, $E>100$ GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background…

High Energy Astrophysical Phenomena · Physics 2015-08-06 S. Archambault , A. Archer , M. Beilicke , W. Benbow , R. Bird , J. Biteau , A. Bouvier , V. Bugaev , J. V Cardenzana , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , H. J. Dickinson , J. Dumm , J. D. Eisch , M. Errando , A. Falcone , Q. Feng , J. P. Finley , H. Fleischhack , P. Fortin , L. Fortson , A. Furniss , G. H. Gillanders , S. Griffin , S. T. Griffiths , J. Grube , G. Gyuk , N. Håkansson , D. Hanna , J. Holder , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , M. Kertzman , Y. Khassen , D. Kieda , M. Krause , F. Krennrich , S. Kumar , M. J. Lang , G. Maier , S. McArthur , A. McCann , K. Meagher , J. Millis , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faoláin de Bhróithe , R. A. Ong , A. N. Otte , N. Park , M. Pohl , A. Popkow , H. Prokoph , E. Pueschel , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , G. T. Richards , E. Roache , M. Santander , G. H. Sembroski , K. Shahinyan , A. W. Smith , D. Staszak , I. Telezhinsky , J. V. Tucci , J. Tyler , A. Varlotta , S. Vincent , S. P. Wakely , A. Weinstein , R. Welsing , A. Wilhelm , D. A. Williams , B. Zitzer , Z. D. Hughes

Discovery of very high energy gamma-ray emission from the BL Lac object PKS 0301-243 with H.E.S.S

The active galactic nucleus PKS 0301-243 (z=0.266) is a high-synchrotron-peaked BL Lac object that is detected at high energies (HE, 100 MeV < E < 100 GeV) by Fermi/LAT. This paper reports on the discovery of PKS 0301-243 at very high…

High Energy Astrophysical Phenomena · Physics 2015-06-17 H. E. S. S. Collaboration , A. Abramowski , F. Acero , F. Aharonian , F. Ait , A. G. Akhperjanian , E. Angüner , G. Anton , S. Balenderan , A. Balzer , A. Barnacka , Y. Becherini , J. Becker , K. Bernlöhr , E. Birsin , E. Bissaldi , J. Biteau , M. Böttcher , C. Boisson , J. Bolmont , P. Bordas , J. Brucker , F. Brun , P. Brun , T. Bulik , S. Carrigan , S. Casanova , M. Cerruti , P. M. Chadwick , R. Chalme-Calvet , R. C. G. Chaves , A. Cheesebrough , M. Chrétien , S. Colafrancesco , G. Cologna , J. Conrad , C. Couturier , M. Dalton , M. K. Daniel , I. D. Davids , B. Degrange , C. Deil , P. deWilt , H. J. Dickinson , A. Djannati-Ataï , W. Domainko , L. O'C. Drury , G. Dubus , K. Dutson , J. Dyks , M. Dyrda , T. Edwards , K. Egberts , P. Eger , P. Espigat , C. Farnier , S. Fegan , F. Feinstein , M. V. Fernandes , D. Fernandez , A. Fiasson , G. Fontaine , A. Förster , M. Füssling , M. Gajdus , Y. A. Gallant , T. Garrigoux , B. Giebels , J. F. Glicenstein , M. -H. Grondin , M. Grudzìnska , S. Häffner , J. D. Hague , J. Hahn , J. Harris , G. Heinzelmann , G. Henri , G. Hermann , O. Hervet , A. Hillert , J. A. Hinton , W. Hofmann , P. Hofverberg , M. Holler , D. Horns , A. Jacholkowska , C. Jahn , M. Jamrozy , M. Janiak , F. Jankowsky , I. Jung , M. A. Kastendieck , K. Katarzyński , U. Katz , S. Kaufmann , B. Khélifi , M. Kieffer , S. Klepser , D. Klochkov , W. Kluźniak , T. Kneiske , D. Kolitzus , Nu. Komin , K. Kosack , S. Krakau , F. Krayzel , P. P. Krüger , H. Laffon , G. Lamanna , J. Lefaucheur , M. Lemoine-Goumard , J. -P. Lenain , D. Lennarz , T. Lohse , A. Lopatin , C. -C. Lu , V. Marandon , A. Marcowith , R. Marx , G. Maurin , N. Maxted , M. Mayer , T. J. L. McComb , M. C. Medina , J. Méhault , U. Menzler , M. Meyer , R. Moderski , M. Mohamed , E. Moulin , T. Murach , C. L. Naumann , M. de Naurois , D. Nedbal , J. Niemiec , S. J. Nolan , L. Oakes , S. Ohm , E. de Oña Wilhelmi , B. Opitz , M. Ostrowski , I. Oya , M. Panter , R. D. Parsons , M. Paz Arribas , N. W. Pekeur , G. Pelletier , J. Perez , P. -O. Petrucci , B. Peyaud , S. Pita , H. Poon , G. Pühlhofer , M. Punch , A. Quirrenbach , S. Raab , M. Raue , A. Reimer , O. Reimer , M. Renaud , R. de los Reyes , F. Rieger , L. Rob , S. Rosier-Lees , G. Rowell , B. Rudak , C. B. Rulten , V. Sahakian , D. A. Sanchez , A. Santangelo , R. Schlickeiser , F. Schüssler , A. Schulz , U. Schwanke , S. Schwarzburg , S. Schwemmer , H. Sol , G. Spengler , F. Spies , L. Stawarz , R. Steenkamp , C. Stegmann , F. Stinzing , K. Stycz , I. Sushch , A. Szostek , J. -P. Tavernet , R. Terrier , M. Tluczykont , C. Trichard , K. Valerius , C. van Eldik , G. Vasileiadis , C. Venter , A. Viana , P. Vincent , H. J. Völk , F. Volpe , M. Vorster , S. J. Wagner , P. Wagner , M. Ward , M. Weidinger , Q. Weitzel , R. White , A. Wierzcholska , P. Willmann , A. Wörnlein , D. Wouters , M. Zacharias , A. Zajczyk , A. A. Zdziarski , A. Zech , H. -S. Zechlin

Ten-year optical monitoring of PKS 0735+178: historical comparison, multiband behaviour and variability timescales

New data and results on the optical behaviour of the blazar PKS 0735+178 are presented. In addition the whole historical light curve, and a new photometric calibration of comparison stars are reported. Optical spectral indexes are…

Astrophysics · Physics 2008-11-26 S. Ciprini , L. O. Takalo , G. Tosti , C. M. Raiteri , M. Fiorucci , M. Villata , G. Nucciarelli , L. Lanteri , K. Nilsson , J. A. Ros

A new insight into the innermost jet regions: probing extreme jet variability with LOFT

Blazars are highly variable sources over timescales that can be as low as minutes. This is the case of the High Energy Peaked BL Lac (HBL) objects showing strong variability in X-rays, which highly correlate with that of the TeV emission.…

High Energy Astrophysical Phenomena · Physics 2015-06-17 I. Donnarumma , A. Tramacere , S. Turriziani , L. Costamante , R. Campana , A. De Rosa , E. Bozzo

Optical and Radio Variability of BL Lacertae

We observed the prototype blazar, BL Lacertae, extensively in optical and radio bands during an active phase in the period 2010--2013 when the source showed several prominent outbursts. We searched for possible correlations and time lags…

High Energy Astrophysical Phenomena · Physics 2015-10-28 Haritma Gaur , Alok C. Gupta , R. Bachev , A. Strigachev , E. Semkov , Paul J. Wiita , A. E. Volvach , Minfeng Gu , A. Agarwal , I. Agudo , M. F. Aller , H. D. Aller , O. M. Kurtanidze , S. O. Kurtanidze , A. Lahteenmaki , S. Peneva , M. G. Nikolashvili , L. A. Sigua , M. Tornikoski , L. N. Volvach

Hunting Very High-Energy ($>$100 GeV) Emitting High-Synchrotron Peaked Blazars

Very-high energy (VHE; $>$100 GeV) $\gamma$-ray emission originates via some of the most extreme particle acceleration processes in the universe. Considering beamed active galactic nuclei, i.e., blazars, only a small fraction, mainly high…

High Energy Astrophysical Phenomena · Physics 2025-12-10 Sushmita Agarwal , Vaidehi S. Paliya

Very High Energy Gamma-Ray Observations of a Strong Flaring Activity in M87 in 2008 February

M87 is the only known non blazar radio galaxy to emit very high energy (VHE) gamma-rays. During a monitoring program of M87, a rapid flare in VHE gamma-rays was detected by the MAGIC telescope in early 2008. The flux was found to be…

Astrophysics · Physics 2011-02-11 MAGIC Collaboration , J. Albert

A Three-Year Multi-Wavelength Study of the Very High Energy Gamma-ray Blazar 1ES 0229+200

The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Gamma ~ 2.5), very-high-energy-emitting (E > 100 GeV) gamma-ray blazar. Very-high-energy measurements of this active galactic…

High Energy Astrophysical Phenomena · Physics 2015-06-18 E. Aliu , S. Archambault , T. Arlen , T. Aune , B. Behera , M. Beilicke , W. Benbow , K. Berger , R. Bird , A. Bouvier , J. H. Buckley , V. Bugaev , K. Byrum , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , C. Duke , J. Dumm , M. Errando , A. Falcone , S. Federici , Q. Feng , J. P. Finley , H. Fleischhack , P. Fortin , L. Fortson , A. Furniss , N. Galante , G. H. Gillanders , S. Griffin , S. T. Griffiths , J. Grube , G. Gyuk , D. Hanna , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , M. Kertzman , Y. Khassen , D. Kieda , H. Krawczynski , F. Krennrich , M. J. Lang , A. S Madhavan , G. Maier , P. Majumdar , S. McArthur , A. McCann , K. Meagher , J. Millis , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faolain de Bhroithe , R. A. Ong , A. N. Otte , N. Park , J. S. Perkins , M. Pohl , A. Popkow , H. Prokoph , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , G. T. Richards , E. Roache , G. H. Sembroski , A. W. Smith , D. Staszak , I. Telezhinsky , M. Theiling , A. Varlotta , V. V. Vassiliev , S. Vincent , S. P. Wakely , T. C. Weekes , A. Weinstein , R. Welsing , D. A. Williams , A. Zajczyk , B. Zitzer

A First Synoptic Blazar Study Comprising Thirteen Blazars Visible in E>100 GeV Gamma-Rays

Since 2002, the number of detected blazars at E_\gamma > 100 GeV has more than doubled. I study all currently known BL Lac-type objects with published energy spectra. Their intrinsic energy spectra are reconstructed by removing…

Astrophysics · Physics 2009-01-08 Robert Wagner

VERITAS detection of gamma-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations

During May 2013, a gamma-ray flare from the BL Lac object 1ES 1727+502 (z=0.055) has been detected with the VERITAS Cherenkov telescopes. This detection represents the first evidence of very-high-energy (E>100 GeV) variability from this…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Matteo Cerruti