Related papers: VERITAS Blazar Observations - Recent Results

Simultaneous multi-frequency observations of PG 1553+113

We report simultaneous multi-frequency observations of the blazar PG 1553+113, that were carried out in March-April 2008. Optical, X-ray, high-energy (HE; greater than 100 MeV) gamma-ray, and very-high- energy (VHE; greater than 100 GeV)…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Nijil Mankuzhiyil , Daniela Dorner , Elisa Prandini , Massimo Persic , Elena Pian , Filippo D'Ammando , Stefano Vercellone

STACEE Observations of 1ES 1218+304

We present the analysis and results of recent high-energy gamma-ray observations of the high energy-peaked BL Lac (HBL) object 1ES 1218+304 with the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE). 1ES 1218+304 is an X-ray…

Astrophysics · Physics 2007-10-24 STACEE Collaboration , R. Mukherjee , N. Akhter , J. Ball , J. E. Carson , C. E. Covault , D. D. Driscoll , P. Fortin , D. M. Gingrich , D. S. Hanna , A. Jarvis , J. Kildea , T. Lindner , C. Mueller , R. A. Ong , K. Ragan , D. A. Williams , J. Zweerink

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

Unraveling The Complex Nature Of The Very High-Energy $\gamma$-Ray Blazar PKS 2155-304

PKS 2155-304 is a blazar located in the Southern Hemisphere, monitored with the High Energy Stereoscopic System (H.E.S.S.) at very high energy (VHE, E>100 GeV) $\gamma$ rays every year since 2002. Thanks to the large data set collected in…

High Energy Astrophysical Phenomena · Physics 2019-12-05 Alicja Wierzcholska , Michael Zacharias , Felix Jankowsky , Stefan Wagner , H. E. S. S. Collaboration

The 2012 flare of PG 1553+113 seen with H.E.S.S. and Fermi-LAT

Very high energy (VHE, $E>$100 GeV) $\gamma$-ray flaring activity of the high-frequency peaked BL Lac object \pg\ has been detected by the \hess\ telescopes. The flux of the source increased by a factor of 3 during the nights of 2012 April…

High Energy Astrophysical Phenomena · Physics 2016-08-07 A. Abramowski , F. Aharonian , F. Ait Benkhali , A. G. Akhperjanian , E. O. Angüner , M. Backes , S. Balenderan , A. Balzer , A. Barnacka , Y. Becherini , J. Becker Tjus , D. Berge , S. Bernhard , K. Bernlöhr , E. Birsin , J. Biteau , M. Böttcher , C. Boisson , J. Bolmont , P. Bordas , J. Bregeon , F. Brun , P. Brun , M. Bryan , T. Bulik , S. Carrigan , S. Casanova , P. M. Chadwick , N. Chakraborty , R. Chalme-Calvet , R. C. G. Chaves , M. Chrétien , S. Colafrancesco , G. Cologna , J. Conrad , C. Couturier , Y. Cui , M. Dalton , I. D. Davids , B. Degrange , C. Deil , P. deWilt , A. Djannati-Ataï , W. Domainko , A. Donath , 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 , S. Gabici , M. Gajdus , Y. A. Gallant , T. Garrigoux , G. Giavitto , B. Giebels , J. F. Glicenstein , D. Gottschall , M. -H. Grondin , M. Grudzińska , D. Hadsch , S. Häffner , 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. Ivascenko , 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 , D. Kolitzus , Nu. Komin , K. Kosack , S. Krakau , F. Krayzel , P. P. Krüger , H. Laffon , G. Lamanna , J. Lefaucheur , V. Lefranc , A. Lemière , M. Lemoine-Goumard , J. -P. Lenain , T. Lohse , A. Lopatin , C. -C. Lu , V. Marandon , A. Marcowith , R. Marx , G. Maurin , N. Maxted , M. Mayer , T. J. L. McComb , J. Méhault , P. J. Meintjes , U. Menzler , M. Meyer , A. M. W. Mitchell , R. Moderski , M. Mohamed , K. Morå , E. Moulin , T. Murach , M. de Naurois , J. Niemiec , S. J. Nolan , L. Oakes , H. Odaka , S. Ohm , 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 , I. Reichardt , A. Reimer , O. Reimer , M. Renaud , R. de los Reyes , F. Rieger , L. Rob , C. Romoli , S. Rosier-Lees , G. Rowell , B. Rudak , C. B. Rulten , V. Sahakian , D. Salek , D. A. Sanchez , A. Santangelo , R. Schlickeiser , F. Schüssler , A. Schulz , U. Schwanke , S. Schwarzburg , S. Schwemmer , H. Sol , F. Spanier , G. Spengler , F. Spies , Ł. Stawarz , R. Steenkamp , C. Stegmann , F. Stinzing , K. Stycz , I. Sushch , J. -P. Tavernet , T. Tavernier , A. M. Taylor , R. Terrier , M. Tluczykont , C. Trichard , K. Valerius , C. van Eldik , B. van Soelen , G. Vasileiadis , J. Veh , C. Venter , A. Viana , P. Vincent , J. Vink , H. J. Völk , F. Volpe , M. Vorster , T. Vuillaume , P. Wagner , R. M. Wagner , M. Ward , M. Weidinger , Q. Weitzel , R. White , A. Wierzcholska , P. Willmann , A. Wörnlein , D. Wouters , R. Yang , V. Zabalza , D. Zaborov , M. Zacharias , A. A. Zdziarski , A. Zech , H. -S. Zechlin

Observation of X-ray variability in the BL Lac object 1ES1959+65

This paper reports X-ray spectral observations of a relatively nearby z = 0.048 BL Lacertae (BL Lac) object 1ES1959+650, which is a potential TeV emitter. The observations include 31 short pointings made by the Unconventional Stellar Aspect…

Astrophysics · Physics 2008-11-26 Berrie Giebels , Elliott D. Bloom , Warren Focke , Gary Godfrey , Greg Madejski , Kaice T. Reilly , Pablo M. Saz Parkinson , Ganya Shabad , Reba M. Bandyopadhyay , Gilbert G. Fritz , Paul Hertz , Michael P. Kowalski , Michael P. Kowalski , Michael N. Lovellette , Paul S. Ray , Michael T. Wolff , Kent S. Wood , Daryl J. Yentis , Jeffrey D. Scargle

The exceptional VHE gamma-ray outburst of PKS 1510-089 in May 2016

PKS 1510-089 (z=0.361) is one of only a handful of flat spectrum radio quasars that have been detected at very high energy (VHE, $E>100\,$GeV) gamma rays. It is a very active source across the entire electromagnetic spectrum. VHE…

High Energy Astrophysical Phenomena · Physics 2020-01-30 Michael Zacharias , Julian Sitarek , Dijana Dominis Prester , Felix Jankowsky , Elina Lindfors , Mahmoud Mohamed , David Sanchez , Tomislav Terzic

The detection of the blazar S4 0954+65 at very-high-energy with the MAGIC telescopes during an exceptionally high optical state

The very-high-energy (VHE, $\gtrsim 100$ GeV) $\gamma$-ray MAGIC observations of the blazar S4 0954+65, were triggered by an exceptionally high flux state of emission in the optical. This blazar has a disputed redshift of z=0.368 or…

High Energy Astrophysical Phenomena · Physics 2019-08-15 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 , 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 , 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. Kuvež dić , 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 , J. Becerra González , Y. Tanaka , R. Ojha , J. Finke , A. Lähteenmäki , E. Järvelä , M. Tornikoski , V. Ramakrishnan , T. Hovatta , S. G. Jorstad , A. P. Marscher , V. M. Larionov , G. A. Borman , T. S. Grishina , E. N. Kopatskaya , L. V. Larionova , D. A. Morozova , S. S. Savchenko , Yu. V. Troitskaya , I. S. Troitsky , A. A. Vasilyev , I. Agudo , S. N. Molina , C. Casadio , M. Gurwell , M. I. Carnerero , C. Protasio , J. A Acosta Pulido

Discovery and identification of two gamma-ray blazars at low galactic latitude with VERITAS

We report on the discovery of two gamma-ray sources at E > 200 GeV with VERITAS: RX J0648.7+1516 and VER J0521+211. Both sources are located at low galactic latitudes (|b| < 10 deg), and were previously classified as active galactic nuclei…

High Energy Astrophysical Phenomena · Physics 2019-08-13 M. Errando

Multiwavelength observations of the blazar BL Lacertae: a new fast TeV gamma-ray flare

Combined with very-long-baseline interferometry measurements, the observations of fast TeV gamma-ray flares probe the structure and emission mechanism of blazar jets. However, only a handful of such flares have been detected to date, and…

High Energy Astrophysical Phenomena · Physics 2018-06-08 A. U. Abeysekara , W. Benbow , R. Bird , T. Brantseg , R. Brose , M. Buchovecky , J. H. Buckley , V. Bugaev , M. P. Connolly , W. Cui , M. K. Daniel , A. Falcone , Q. Feng , J. P. Finley , L. Fortson , A. Furniss , G. H. Gillanders , I. Gunawardhana , M. Hütten , D. Hanna , O. Hervet , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , M. Kertzman , F. Krennrich , M. J. Lang , T. T. Y. Lin , S. McArthur , P. Moriarty , R. Mukherjee , S. O'Brien , R. A. Ong , A. N. Otte , N. Park , A. Petrashyk , M. Pohl , E. Pueschel , J. Quinn , K. Ragan , P. T. Reynolds , G. T. Richards , E. Roache , C. Rulten , I. Sadeh , M. Santander , G. H. Sembroski , K. Shahinyan , S. P. Wakely , A. Weinstein , R. M. Wells , P. Wilcox , D. A. Williams , B. Zitzer , S. G. Jorstad , A. P. Marscher , M. L. Lister , Y. Y. Kovalev , A. B. Pushkarev , T. Savolainen , I. Agudo , S. N. Molina , J. L. Gómez , V. M. Larionov , G. A. Borman , A. A. Mokrushina , M. Tornikoski , A. Lähteenmäki , W. Chamani , S. Enestam , S. Kiehlmann , T. Hovatta , P. S. Smith , P. Pontrelli

Variability Study of Extreme Blazars with VERITAS

The VERITAS array of imaging atmospheric Cherenkov telescopes has collected nearly 6000 hours of observations of active galactic nuclei (AGNs). It has detected 39 very-high-energy (VHE, >100 GeV) AGNs at redshifts up to z = 0.9, of which 24…

High Energy Astrophysical Phenomena · Physics 2019-08-09 Orel Gueta

VERITAS Observations of Mgro J1908+06/Hess J1908+063

The unidentified TeV gamma-ray source MGRO J1908+06/HESS J1908+063 was observed with the VERITAS Imaging Atmospheric Cherenkov Array during October 2007 and May-June 2008. This extended source is located on the galactic plane at a galactic…

Astrophysics · Physics 2019-08-13 John E Ward

MAGIC discovery and multiwavelength observations of the BL Lac 1ES 1727+502

Blazars, active galactic nuclei whose jet axis is pointed towards the observer, constitute the most numerous class of extragalactic very high energy (VHE, E > 100\, GeV) gamma-ray emitters. The MAGIC experiment, a system of two Imaging…

High Energy Astrophysical Phenomena · Physics 2019-08-14 K. Berger , G. De Caneva , E. Lindfors , S. Lombardi , A. Stamerra , F. Tavecchio

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

Highlights from the VERITAS Blazar Program

VERITAS is an array of four 12-m imaging Cherenkov telescopes, sensitive to gamma rays in the energy range from 85 GeV to 30 TeV. VERITAS dedicates roughly 40% of its total observing time to blazars. We present recent highlights from the…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Jon Dumm

Observation of selected IBLs and LBLs with VERITAS

The improved sensitivity of current-generation atmospheric-Cherenkov telescope (ACT) arrays enables us to probe for the first time low-frequency-peaked and intermediate-frequency-peaked BL Lac (LBL and IBL, respectively) objects as very…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Pratik Majumdar

VERITAS and H.E.S.S. observations of the gamma-ray binary HESS J0632+057

HESS J0632+057 has been recently identified as a new gamma-ray binary system. The source, located in the Monoceros region and associated with the massive Be star MWC 148, shows variability from radio to very high energy (VHE) gamma-rays,…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Pol Bordas , Gernot Maier

Multi-wavelength Observations of VHE BL Lac Objects

We present multi-wavelength observations of the very high energy (VHE, E >250 GeV) gamma-ray sources Mrk 421 and Mrk 501. The VHE data presented here were taken with the Whipple Observatory 10m gamma-ray telescope. In the Mrk 421 campaign,…

Astrophysics · Physics 2019-08-14 M. Catanese

Discovery of Very High Energy Gamma-Ray Emission from the BL Lac Object H2356-309 with the H.E.S.S. Cherenkov Telescopes

The extreme synchrotron BL Lac object H2356-309, located at a redshift of z = 0.165, was observed from June to December 2004 with a total exposure of approx. 40 h live-time with the H.E.S.S. (High Energy Stereoscopic System) array of…

Astrophysics · Physics 2009-11-11 Aharonian et al.

An emerging population of BL Lacs with extreme properties: towards a class of EBL and cosmic magnetic field probes?

High energy observations of extreme BL Lac objects, such as 1ES 0229+200 or 1ES 0347-121, recently focused interest both for blazar and jet physics and for the implication on the extragalactic background light and intergalactic magnetic…

High Energy Astrophysical Phenomena · Physics 2015-06-25 Giacomo Bonnoli , Fabrizio Tavecchio , Gabriele Ghisellini , Tullia Sbarrato