Related papers: Multiwavelength observations of a TeV-Flare from W…

Status And Highlights Of VERITAS

VERITAS (Very Energetic Radiation Imaging Telescope Array System) is an array of atmospheric Cherenkov telescopes sensitive to very high energy (VHE) gamma-rays above 100 GeV. Located at the Fred Lawrence Whipple Observatory in southern…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Nicola Galante

Very High Energy Gamma-Ray Observations of the Galactic Centre Region

Recent progress in pushing the sensitivity of the Imaging Atmospheric Cherenkov Technique into the 10 mCrab regime has enabled first sensitive observations of the innermost few 100 pc of the Milky Way in Very High Energy (VHE; >100 GeV)…

Astrophysics · Physics 2009-11-13 Christopher van Eldik

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

A thirteen-year-long broadband view of BL Lac

We present the results of an extensive analysis of the optical, ultraviolet, X-ray and $\gamma$-ray data collected from the observations of the BL Lac objects prototype BL Lacertae carried out over a period of nearly 13 years, between…

High Energy Astrophysical Phenomena · Physics 2022-04-20 N. Sahakyan , P. Giommi

Coordinated Multiwavelength Observations of BL Lacertae in 2000

BL Lacertae was the target of an extensive multiwavelength monitoring campaign in the second half of 2000. Simultaneous or quasi-simultaneous observations were taken at radio (UMRAO and Metsaehovi) and optical(WEBT collaboration)…

Astrophysics · Physics 2009-11-10 M. Boettcher

Very High Energy Gamma-ray spectral properties of Mrk 501 from CAT Cerenkov telescope observations in 1997

The BL Lac object Mrk 501 went into a very high state of activity during 1997, both in VHE gamma-rays and X-rays. We present here results from observations at energies above 250 GeV carried out between March and October 1997 with the CAT…

Astrophysics · Physics 2007-05-23 A. Djannati-Atai , F. Piron , A. Barrau , L. Iacoucci , M. Punch , J. -P. Tavernet , R. Bazer-Bachi , H. Cabot , L. -M. Chounet , G. Debiais , B. Degrange , J. -P. Dezalay , D. Dumora , P. Espigat , B. Fabre , P. Fleury , G. Fontaine , C. Ghesquière , P. Goret , C. Gouiffes , I. A. Grenier , S. Le Bohec , I. Malet , C. Meynadier , G. Mohanty , E. Nuss , E. Paré , J. Québert , K. Ragan , C. Renault , M. Rivoal , L. Rob , K. Schahmaneche , D. A. Smith

Rapid Synchrotron Flares from BL Lacertae Detected by ASCA and RXTE

We report the variable X-ray emission from BL Lacertae detected in the ASCA ToO observation conducted during the EGRET and RXTE pointings, coincident with the 1997 July outburst. The source showed a historically high state of X-ray,…

Astrophysics · Physics 2009-10-31 C. Tanihata , T. Takahashi , J. Kataoka , G. M. Madejski , S. Inoue , H. Kubo , F. Makino , J. R. Mattox , N. Kawai

Detection of Vhe Gamma-Rays from MRK 501 with the Cat Imaging Telescope

The CAT imaging telescope on the site on the former solar plant Themis has been observing gamma-rays from Mrk501 above 220 GeV in March and April 1997. This source is shown to be highly variable and the light curve is presented. The…

Astrophysics · Physics 2007-05-23 A. Barrau , R. Bazer-Bachi , H. Cabot , L. M. Chounet , G. Debiais , B. Degrange , J. P. Dezalay , A. Djannati-Atai , D. Dumora , P. Espigat , B. Fabre , P. Fleury , G. Fontaine , R. George , C. Ghesquiere , P. Goret , C. Gouiffes , I. A. Grenier , L. Iacoucci , S. Le Bohec , I. Mallet , C. Meynadier , F. Munz , T. A. Palfrey , E. Pare , Y. Pons , M. Punch , J. Quebert , K. Ragan , C. Renault , M. Rivoal , L. Rob , P. Schovanek , D. Smith , J. P. Tavernet , J. Vrana

VERITAS follow-up observation of the BL Lac blazar B2 1811+31 2020 Flare

VERITAS is an imaging atmospheric Cherenkov telescope (IACT) array most sensitive to gamma rays in the very-high-energy (VHE) energy band (85 GeV - 30 TeV). As a part of its active galactic nuclei (AGN) program, VERITAS focuses on the…

High Energy Astrophysical Phenomena · Physics 2023-09-25 Pablo Drake , Colin Adams

Multiwavelength Observations of Mrk 501 in 2008

The well-studied VHE (E >100 GeV) blazar Mrk 501 was observed between March and May 2008 as part of an extensive multiwavelength observation campaign including radio, optical, X-ray and VHE gamma-ray instruments. Mrk 501 was in a low state…

High Energy Astrophysical Phenomena · Physics 2009-07-08 D. Kranich , D. Paneque , A. Cesarini , A. Falcone , M. Giroletti , E. Hoversten , T. Hovatta , Y. Y. Kovalev , A. Lahteenmaki , E. Nieppola , C. Pagani , A. Pichel , K. Satalecka , J. Scargle , D. Steele , F. Tavecchio , D. Tescaro , M. Tornikoski , M. Villata

HESS J1943+213: An Extreme Blazar Shining Through The Galactic Plane

HESS J1943+213 is a very-high-energy (VHE; $>$100 GeV) $\gamma$-ray source in the direction of the Galactic Plane. Studies exploring the classification of the source are converging towards its identification as an extreme synchrotron BL Lac…

High Energy Astrophysical Phenomena · Physics 2018-08-29 The VERITAS Collaboration , A. Archer , W. Benbow , R. Bird , R. Brose , M. Buchovecky , V. Bugaev , W. Cui , M. K. Daniel , A. Falcone , Q. Feng , J. P. Finley , A. Flinders , L. Fortson , A. Furniss , G. H. Gillanders , M. Hütten , D. Hanna , O. Hervet , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , N. Kelley-Hoskins , D. Kieda , M. Krause , F. Krennrich , S. Kumar , M. J. Lang , T. T. Y. Lin , S. McArthur , P. Moriarty , R. Mukherjee , D. Nieto , S. O'Brien , R. A. Ong , A. N. Otte , N. Park , A. Petrashyk , M. Pohl , A. Popkow , E. Pueschel , J. Quinn , K. Ragan , P. T. Reynolds , G. T. Richards , E. Roache , C. Rulten , I. Sadeh , G. H. Sembroski , K. Shahinyan , J. Tyler , S. P. Wakely , O. M. Weiner , A. Weinstein , R. M. Wells , P. Wilcox , A. Wilhelm , D. A. Williams , W. F. Brisken , P. Pontrelli

Observations of the unidentified gamma-ray source TeV J2032+4130 by VERITAS

TeV J2032+4130 was the first unidentified source discovered at very high energies (VHE; E $>$ 100 GeV), with no obvious counterpart in any other wavelength. It is also the first extended source to be observed in VHE gamma rays. Following…

High Energy Astrophysical Phenomena · Physics 2015-06-18 VERITAS Collaboration , E. Aliu , T. Aune , B. Behera , M. Beilicke , W. Benbow , K. Berger , R. Bird , J. H. Buckley , V. Bugaev , J. V Cardenzana , 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 , 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 , O. Kargaltsev , P. Kaaret , M. Kertzman , Y. Khassen , D. Kieda , H. Krawczynski , M. J. Lang , A. S Madhavan , G. Maier , P. Majumdar , A. McCann , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faolain de Bhroithe , R. A. Ong , A. N. Otte , D. Pandel , J. S. Perkins , 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 , C. Skole , D. Staszak , I. Telezhinsky , M. Theiling , J. V. Tucci , J. Tyler , A. Varlotta , S. Vincent , S. P. Wakely , T. C. Weekes , A. Weinstein , R. Welsing , D. A. Williams , B. Zitzer

Very high energy $\gamma$-ray emission from RBS 0679

In this paper we report the \textit{Fermi} Large Area Telescope (LAT) detection of Very High Energy (VHE; $E_{\gamma}>100$ GeV) $\gamma$-ray emission from the BL Lac object RBS 0679. $5.3$ years of LAT observations revealed the presence of…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Anthony M. Brown , Paula M. Chadwick , Hermine Landt

High zenith angle observations of PKS 2155-304 with the MAGIC telescope

The high frequency peaked BL Lac PKS 2155-304 with a redshift z=0.116 was discovered 1997 in the VHE range by the University of Durham Mark 6 gamma-ray telescope in Australia with a flux corresponding to approx. 0.2 times the Crab Nebula…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-13 D. Hadasch , T. Bretz , D. Mazin

The first Fermi multifrequency campaign on BL Lacertae: characterizing the low-activity state of the eponymous blazar

We report on observations of BL Lacertae during the first 18 months of Fermi-LAT science operations and present results from a 48-day multifrequency coordinated campaign from 2008 August 19 to 2008 October 7. The radio to gamma-ray behavior…

High Energy Astrophysical Phenomena · Physics 2015-05-27 A. A. Abdo

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622 + 3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High Altitude Air Shower Observatory (LHAASO). The source is detected…

High Energy Astrophysical Phenomena · Physics 2026-01-07 The LHAASO collabration , Zhen Cao , F. Aharonian , Y. X. Bai , Y. W. Bao , D. Bastieri , X. J. Bi , Y. J. Bi , W. Bian , A. V. Bukevich , C. M. Cai , W. Y. Cao , Zhe Cao , J. Chang , J. F. Chang , A. M. Chen , E. S. Chen , G. H. Chen , H. X. Chen , Liang Chen , Long Chen , M. J. Chen , M. L. Chen , Q. H. Chen , S. Chen , S. H. Chen , S. Z. Chen , T. L. Chen , X. B. Chen , X. J. Chen , Y. Chen , N. Cheng , Y. D. Cheng , M. C. Chu , M. Y. Cui , S. W. Cui , X. H. Cui , Y. D. Cui , B. Z. Dai , H. L. Dai , Z. G. Dai , Danzengluobu , Y. X. Diao , X. Q. Dong , K. K. Duan , J. H. Fan , Y. Z. Fan , J. Fang , J. H. Fang , K. Fang , C. F. Feng , H. Feng , L. Feng , S. H. Feng , X. T. Feng , Y. Feng , Y. L. Feng , S. Gabici , B. Gao , C. D. Gao , Q. Gao , W. Gao , W. K. Gao , M. M. Ge , T. T. Ge , L. S. Geng , G. Giacinti , G. H. Gong , Q. B. Gou , M. H. Gu , F. L. Guo , J. Guo , X. L. Guo , Y. Q. Guo , Y. Y. Guo , Y. A. Han , O. A. Hannuksela , M. Hasan , H. H. He , H. N. He , J. Y. He , X. Y. He , Y. He , S. Hernández-Cadena , B. W. Hou , C. Hou , X. Hou , H. B. Hu , S. C. Hu , C. Huang , D. H. Huang , J. J. Huang , T. Q. Huang , W. J. Huang , X. T. Huang , X. Y. Huang , Y. Huang , Y. Y. Huang , X. L. Ji , H. Y. Jia , K. Jia , H. B. Jiang , K. Jiang , X. W. Jiang , Z. J. Jiang , M. Jin , S. Kaci , M. M. Kang , I. Karpikov , D. Khangulyan , D. Kuleshov , K. Kurinov , B. B. Li , Cheng Li , Cong Li , D. Li , F. Li , H. B. Li , H. C. Li , Jian Li , Jie Li , K. Li , L. Li , R. L. Li , S. D. Li , T. Y. Li , W. L. Li , X. R. Li , Xin Li , Y. Li , Y. Z. Li , Zhe Li , Zhuo Li , E. W. Liang , Y. F. Liang , S. J. Lin , B. Liu , C. Liu , D. Liu , D. B. Liu , H. Liu , H. D. Liu , J. Liu , J. L. Liu , J. R. Liu , M. Y. Liu , R. Y. Liu , S. M. Liu , W. Liu , X. Liu , Y. Liu , Y. Liu , Y. N. Liu , Y. Q. Lou , Q. Luo , Y. Luo , H. K. Lv , B. Q. Ma , L. L. Ma , X. H. Ma , J. R. Mao , Z. Min , W. Mitthumsiri , G. B. Mou , H. J. Mu , A. Neronov , K. C. Y. Ng , M. Y. Ni , L. Nie , L. J. Ou , P. Pattarakijwanich , Z. Y. Pei , J. C. Qi , M. Y. Qi , J. J. Qin , A. Raza , C. Y. Ren , D. Ruffolo , A. Sáiz , D. Semikoz , L. Shao , O. Shchegolev , Y. Z. Shen , X. D. Sheng , Z. D. Shi , F. W. Shu , H. C. Song , Yu. V. Stenkin , V. Stepanov , Y. Su , D. X. Sun , H. Sun , Q. N. Sun , X. N. Sun , Z. B. Sun , N. H. Tabasam , J. Takata , P. H. T. Tam , H. B. Tan , Q. W. Tang , R. Tang , Z. B. Tang , W. W. Tian , C. N. Tong , L. H. Wan , C. Wang , G. W. Wang , H. G. Wang , J. C. Wang , K. Wang , Kai Wang , Kai Wang , L. P. Wang , L. Y. Wang , L. Y. Wang , R. Wang , W. Wang , X. G. Wang , X. J. Wang , X. Y. Wang , Y. Wang , Y. D. Wang , Z. H. Wang , Z. X. Wang , Zheng Wang , D. M. Wei , J. J. Wei , Y. J. Wei , T. Wen , S. S. Weng , C. Y. Wu , H. R. Wu , Q. W. Wu , S. Wu , X. F. Wu , Y. S. Wu , S. Q. Xi , J. Xia , J. J. Xia , G. M. Xiang , D. X. Xiao , G. Xiao , Y. L. Xin , Y. Xing , D. R. Xiong , Z. Xiong , D. L. Xu , R. F. Xu , R. X. Xu , W. L. Xu , L. Xue , D. H. Yan , T. Yan , C. W. Yang , C. Y. Yang , F. F. Yang , L. L. Yang , M. J. Yang , R. Z. Yang , W. X. Yang , Z. H. Yang , Z. G. Yao , X. A. Ye , L. Q. Yin , N. Yin , X. H. You , Z. Y. You , Q. Yuan , H. Yue , H. D. Zeng , T. X. Zeng , W. Zeng , X. T. Zeng , M. Zha , B. B. Zhang , B. T. Zhang , C. Zhang , F. Zhang , H. Zhang , H. M. Zhang , H. Y. Zhang , J. L. Zhang , Li Zhang , P. F. Zhang , P. P. Zhang , R. Zhang , S. R. Zhang , S. S. Zhang , W. Y. Zhang , X. Zhang , X. P. Zhang , Yi Zhang , Yong Zhang , Z. P. Zhang , J. Zhao , L. Zhao , L. Z. Zhao , S. P. Zhao , X. H. Zhao , Z. H. Zhao , F. Zheng , W. J. Zhong , B. Zhou , H. Zhou , J. N. Zhou , M. Zhou , P. Zhou , R. Zhou , X. X. Zhou , X. X. Zhou , B. Y. Zhu , C. G. Zhu , F. R. Zhu , H. Zhu , K. J. Zhu , Y. C. Zou , X. Zuo

The TeV emission of Ap Librae: a hadronic interpretation and prospects for CTA

Ap Librae is one out of a handful of low-frequency peaked blazars to be detected at TeV $\gamma$-rays and the only one with an identified X-ray jet. Combined observations of Fermi-LAT at high energies (HE) and of H.E.S.S at very high…

High Energy Astrophysical Phenomena · Physics 2016-11-15 Maria Petropoulou , Georgios Vasilopoulos , Dimitrios Giannios

On the Location of the Gamma-ray Emission in the 2008 Outburst in the BL Lacertae Object AO 0235+164 through Observations across the Electromagnetic Spectrum

We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization,…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Ivan Agudo , Alan P. Marscher , Svetlana G. Jorstad , Valeri M. Larionov , Jose L. Gomez , Anne Lahteenmaki , Paul S. Smith , Kari Nilsson , Anthony C. S. Readhead , Margo F. Aller , Jochen Heidt , Mark Gurwell , Clemens Thum , Ann E. Wehrle , Maria G. Nikolashvili , Hugh D. Aller , Erika Benitez , Dmitriy A. Blinov , Vladimir A. Hagen-Thorn , David Hiriart , Buell T. Jannuzi , Manasvita Joshi , Givi N. Kimeridze , Omar M. Kurtanidze , Sofia O. Kurtanidze , Elina Lindfors , Sol N. Molina , Daria A. Morozova , Elina Nieppola , Alice R. Olmstead , Riho Reinthal , Mar Roca-Sogorb , Gary D. Schmidt , Lorand A. Sigua , Aimo Sillanpaa , Leo Takalo , Brian Taylor , Merja Tornikoski , Ivan S. Troitsky , Alma C. Zook , Helmut Wiesemeyer

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

TeV Active Galactic Nuclei: Multifrequency Modeling

In the recent years, the new generation of Imaging Atmospheric Cerenkov Telescopes successfully detected very high energy (VHE; E>100 GeV) gamma-ray emission from a growing number of Active Galactic Nuclei (AGNs), mainly belonging to the…

High Energy Astrophysical Phenomena · Physics 2009-07-13 J. -P. Lenain