Related papers: BL Lac: A New Ultrahigh-Energy Gamma-Ray Source

Very High Energy Gamma-Ray Emission from the Blazar Markarian 421

Very high energy gamma-ray emission from the BL Lac object Markarian 421 has been detected over three observing seasons on 59 nights between April 1992 and June 1994 with the Whipple 10-meter imaging Cherenkov telescope. During its initial…

Astrophysics · Physics 2009-10-28 M. S. Schubnell , C. W. Akerlof , S. Biller J. Buckley , D. A. Carter-Lewis , M. F. Cawley , M. Chantell , V. Connaughton , D. J. Fegan , S. Fennell , J. A. Gaidos , A. M. Hillas , A. D. Kerrick R. C. Lamb , D. I. Meyer , G. Mohanty , J. Rose , A. C. Rovero , G. Sembroski , T. C. Weekes , C. Wilson , J. Zweerink

Discovery of transient high-energy gamma-ray emission from the BL Lacertae object 5C 3.178

We report the serendipitous discovery of transient, point-like high energy gamma-ray emission coincident with the position of the suspected BL Lac object 5C 3.178. The source was detected using the Fermi Large Area Telescope (LAT) at a…

High Energy Astrophysical Phenomena · Physics 2013-04-18 Hugh Dickinson , Christian Farnier

Discovery of hard-spectrum \gamma-ray emission from the BL Lac object 1ES 0414+009

1ES 0414+009 (z = 0.287) is a distant high-frequency-peaked BL Lac object, and has long been considered a likely emitter of very-high energy (VHE, E>100 GeV) gamma-rays due to its high X-ray and radio flux. Observations in the VHE gamma-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-03 The 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 , K. Bernlöhr , E. Birsin , J. Biteau , A. Bochow , C. Boisson , J. Bolmont , P. Bordas , 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 , J. Conrad , 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 , K. Egberts , P. Eger , P. Espigat , L. Fallon , C. Farnier , F. Feinstein , M. V. Fernandes , A. Fiasson , G. Fontaine , A. Förster , M. Füßling , Y. A. Gallant , H. Gast , 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. Katarzynski , U. Katz , S. Kaufmann , D. Keogh , D. Khangulyan , B. Khélifi , D. Klochkov W. Kluźniak , T. Kneiske , Nu. Komin , K. Kosack , R. Kossakowski , H. Laffon , G. Lamanna , D. Lennarz , T. Lohse , A. Lopatin , C. -C. Lu , V. Marandon , A. Marcowith , J. Masbou , D. Maurin , N. Maxted , M. Mayer , T. J. L. McComb , M. C. Medina , J. Méhault , R. Moderski , E. Moulin , C. L. Naumann , M. Naumann-Godo , M. de Naurois , D. Nedbal , D. Nekrassov , N. Nguyen , B. Nicholas , J. Niemiec , S. J. Nolan , S. Ohm , E. de Ona 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 , V. Sahakian , D. A. Sanchez , A. Santangelo , R. Schlickeiser , F. M. Schöck , A. Schulz , U. Schwanke , S. Schwarzburg , S. Schwemmer , F. Sheidaei , M. Sikora , J. L. Skilton , H. Sol , G. Spengler , L. Stawarz , R. Steenkamp , C. Stegmann , F. Stinzing , K. Stycz , I. Sushch , A. Szostek , J. -P. Tavernet , R. Terrier , M. Tluczykont , K. Valerius , C. van Eldik , G. Vasileiadis , C. 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 , L. Costamante , S. Fegan , M. Ajello

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.

Detection of the BL Lac object 1ES1426+428 in the Very High Energy gamma-ray band by the CAT Telescope from 1998-2000

The BL Lac Object 1ES 1426+428, at a red-shift of z=0.129, has been monitored by the CAT telescope from February 1998 to June 2000. The accumulation of 26 hours of observations shows a gamma-ray signal of 321 events above 250 GeV at 5.2…

Astrophysics · Physics 2009-11-07 A. Djannati-Atai , B. Khelifi , S. Vorobiov , R. Bazer-Bachi , G. Debiais , B. Degrange , P. Espigat , B. Fabre , G. Fontaine , P. Goret , C. Gouiffes , C. Masterson , F. Piron , M. Punch , M. Rivoal , L. Rob , J. -P. Tavernet

A survey of Active Galaxies with the HAWC Gamma-ray Observatory

The High Altitude Water Cherenkov Gamma-Ray Observatory has been accumulating a progressively deeper exposure of the TeV sky since its inauguration in March 2015. Located at geographical latitude $+19^\circ$N, HAWC has been able to perform…

High Energy Astrophysical Phenomena · Physics 2019-08-20 Alberto Carramiñana , Daniel Rosa González , Sara Coutiño de León , Anna Lia Longinotti

Very high-energy observations of the two high-frequency peaked BL Lac objects 1ES 1218+304 and H 1426+428

We present results of very-high-energy gamma-ray observations (E > 160 GeV) of two high-frequency-peaked BL Lac (HBL) objects, 1ES 1218+304 and H 1426+428, with the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE). Both sources…

High Energy Astrophysical Phenomena · Physics 2011-07-28 C. Mueller , N. Akhter , J. Ball , D. A. Bramel , J. Carson , C. E. Covault , D. Driscoll , P. Fortin , D. M. Gingrich , D. S. Hanna , A. Jarvis , J. Kildea , T. Lindner , R. Mukherjee , R. A. Ong , K. Ragan , R. A. Scalzo , D. A. Williams , J. Zweerink

Discovery of very high-energy gamma-ray emission from the LBL object BL Lacertae

The low-frequency peaked BL Lac (LBL) object BL Lacertae was observed with the MAGIC telescope from 2005 August to December (22.2 hr), and from 2006 July to September (26.0 hr). A very high energy (VHE) gamma-ray signal was discovered with…

Astrophysics · Physics 2007-09-17 MAGIC Collaboration , M. Hayashida , K. Berger , E. Lindfors , V. Vitale , R. Wagner , E. Lorenz

First Results from a Search for TeV Emission from BL Lacs

Two active galactic nuclei have been detected at TeV energies using the atmospheric Cherenkov imaging technique. The Whipple Observatory gamma-ray telescope has been used to observe all the BL Lacertae objects in the northern hemisphere out…

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

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

Gamma-ray counterparts of 2WHSP high-synchrotron-peaked BL Lac objects as possible signatures of ultra-high-energy cosmic-ray emission

We present a search for high-energy $\gamma$-ray emission from 566 Active Galactic Nuclei at redshift $z > 0.2$, from the 2WHSP catalog of high-synchrotron peaked BL Lac objects with eight years of Fermi-LAT data. We focus on a redshift…

High Energy Astrophysical Phenomena · Physics 2020-08-12 Michael W. Toomey , Foteini Oikonomou , Kohta Murase

Temporal and spectral gamma-ray properties of Mkn421 above 250 GeV from CAT observations between 1996 and 2000

The gamma-ray emission above 250 GeV from the BL Lac object Markarian 421 was observed by the CAT Cherenkov imaging telescope between December, 1996, and June, 2000. In 1998, the source produced a series of small flares, making it the…

Astrophysics · Physics 2014-10-13 F. Piron , A. Djannati-Atai , M. Punch , J. -P. Tavernet , A. Barrau , R. Bazer-Bachi , L. -M. Chounet , G. Debiais , B. Degrange , J. -P. Dezalay , P. Espigat , B. Fabre , P. Fleury , G. Fontaine , P. Goret , C. Gouiffes , B. Khelifi , I. Malet , C. Masterson , G. Mohanty , E. Nuss , C. Renault , M. Rivoal , L. Rob , S. Vorobiov

Search for TeV $\gamma$--ray emission from blazar 1ES1218+304 with TACTIC telescope during March-April 2013

In this paper, we present results of TeV $\gamma$--ray observations of the high synchrotron peaked BL Lac object 1ES 1218+304 (z=0.182) with the $TACTIC$ (TeV Atmospheric Cherenkov Telescope with Imaging Camera). The observations are…

High Energy Astrophysical Phenomena · Physics 2015-06-23 K. K. Singh , K. K. Yadav , A. K. Tickoo , R. C. Rannot , P. Chandra , N. K. Agarwal , K. K. Gaur , A. Goyal , H. C. Goyal , N. Kumar , P. Marandi , M. Kothari , H. Bhatt , K. Chanchalani , N. Chouhan , V. K. Dhar , B. Ghosal , S. R. Kaul , M. K. Koul , R. Koul , K. Venugopal , C. K. Bhat , C. Borwankar , J. Bhagwan , A. C. Gupta

HEGRA search for TeV emission from BL Lac objects

The HEGRA system of four Imaging Atmospheric Cherenkov Telescopes (IACTs) has been used to extensively observe extragalactic objects. In this paper we describe the search for TeV emission from nine very promising potential TeV sources,…

Astrophysics · Physics 2007-05-23 F. Aharonian , The HEGRA Collaboration

TeV BL Lac objects at the dawn of the Fermi era

We reconsider the emission properties of the BL Lac objects emitting in the high-energy gamma-ray band exploiting the new information in the MeV-GeV band obtained by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope…

High Energy Astrophysical Phenomena · Physics 2015-05-14 F. Tavecchio , G. Ghisellini , G. Ghirlanda , L. Foschini , L. Maraschi

Detection of TeV Gamma Rays from the BL Lac Object 1ES1959+650 with the Whipple 10m Telescope

We present the first strong detection of very high energy gamma-rays from the close (z=0.048) X-ray selected BL Lacertae object 1ES1959+650. Observations were made with the Whipple 10m telescope on Mt. Hopkins, Arizona, using the…

Astrophysics · Physics 2009-11-07 J. Holder , VERITAS collaboration

TeV gamma-ray observations of southern BL Lacs with the CANGAROO 3.8m Imaging Telescope

Observational and theoretical results indicate that low-redshift BL Lacertae objects are the most likely extragalactic sources to be detectable at TeV energies. In this paper we present the results of observations of 4 BL Lacertae objects…

Astrophysics · Physics 2011-04-04 M. D. Roberts , S. A. Dazeley , P. G. Edwards , T. Hara , Y. Hayami , J. Holder , F. Kakimoto , S. Kamei , A. Kawachi , T. Kifune , R. Kita , T. Konishi , A. Masaike , Y. Matsubara , T. Matsuoka , Y. Mizumoto , M. Mori , H. Muraishi , Y. Muraki , K. Nishijima , S. Oda , S. Ogio , J. R. Patterson , G. P. Rowell , T. Sako , K. Sakurazawa , R. Susukita , A. Suzuki , R. Suzuki , T. Tamura , T. Tanimori , G. J. Thornton , S. Yanagita , T. Yoshida , T. Yoshikoshi

Detection of Very-High Energy Gamma-Rays from the BL Lac Object PG 1553+113 with the MAGIC Telescope

The MAGIC telescope has observed very-high energy gamma-ray emission from the BL Lac object PG 1553+113 in 2005 and 2006 at an overall significance is 8.8 sigma. The light curve shows no significant flux variations on a daily timescale. The…

Astrophysics · Physics 2019-08-15 Robert Wagner , Daniela Dorner , Masaaki Hayashida , Thomas Hengstebeck , Daniel Kranich , Daniel Mazin , Diego Tescaro , Nina Nowak

Discovery of Very High Energy gamma - ray emission from the extreme BL Lac object H2356-309 with H.E.S.S

The understanding of acceleration mechanisms in active galactic nuclei (AGN) jets and the measurement of the extragalactic-background-light (EBL) density are closely linked and require the detection of a large sample of very-high-energy…

Astrophysics · Physics 2016-08-15 S. Pita , W. Benbow , L. Costamante , A. Djannati-Ataï , D. Horns , M. Ouchrif , M. Tluczykont , the HESS Collaboration

Discovery of VHE gamma-ray emission from the BL Lac object B3 2247+381 with the MAGIC telescopes

We study the non-thermal jet emission of the BL Lac object B3 2247+381 during a high optical state. The MAGIC telescopes observed the source during 13 nights between September 30th and October 30th 2010, collecting a total of 14.2 hours of…

High Energy Astrophysical Phenomena · Physics 2016-08-14 The MAGIC Collaboration , J. Aleksić , E. A. Alvarez , L. A. Antonelli , P. Antoranz , M. Asensio , M. Backes , J. A. Barrio , D. Bastieri , J. Becerra González , 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. Cañellas , 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. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , D. Elsaesser , D. Ferenc , M. V. Fonseca , L. Font , C. Fruck , R. J. García López , M. Garczarczyk , D. Garrido , G. Giavitto , N. Godinović , D. Hadasch , D. Häfner , A. Herrero , D. Hildebrand , D. Höhne-Mönch , J. Hose , D. Hrupec , B. Huber , T. Jogler , H. Kellermann , S. Klepser , T. Krähenbühl , J. Krause , A. La Barbera , D. Lelas , E. Leonardo , E. Lindfors , S. Lombardi , M. López , A. López-Oramas , E. Lorenz , M. Makariev , G. Maneva , N. Mankuzhiyil , K. Mannheim , L. Maraschi , M. Mariotti , M. Martínez , D. Mazin , M. Meucci , J. M. Miranda , R. Mirzoyan , H. Miyamoto , J. Moldón , 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. Ribó , 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. Sillanpää , J. Sitarek , I. Snidaric , D. Sobczynska , F. Spanier , S. Spiro , V. Stamatescu , A. Stamerra , B. Steinke , J. Storz , N. Strah , T. Surić , L. Takalo , H. Takami , F. Tavecchio , P. Temnikov , T. Terzić , 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 , V. Kadenius , M. Weidinger , S. Buson