Related papers: Recent Results from the VERITAS Collaboration

The Discovery of gamma-Ray Emission From The Blazar RGB J0710+591

The high-frequency-peaked BL Lacertae object RGB J0710+591 was observed in the very high-energy (VHE; E > 100 GeV) wave band by the VERITAS array of atmospheric Cherenkov telescopes. The observations, taken between 2008 December and 2009…

High Energy Astrophysical Phenomena · Physics 2015-05-18 V. A. Acciari , E. Aliu , T. Arlen , T. Aune , M. Bautista , M. Beilicke , W. Benbow , M. Böttcher , D. Boltuch , S. M. Bradbury , J. H. Buckley , V. Bugaev , K. Byrum , A. Cannon , A. Cesarini , L. Ciupik , W. Cui , R. Dickherber , C. Duke , A. Falcone , J. P. Finley , G. Finnegan , L. Fortson , A. Furniss , N. Galante , D. Gall , K. Gibbs , G. H. Gillanders , S. Godambe , J. Grube , R. Guenette , G. Gyuk , D. Hanna , J. Holder , C. M. Hui , T. B. Humensky , A. Imran , P. Kaaret , N. Karlsson , M. Kertzman , D. Kieda , A. Konopelko , H. Krawczynski , F. Krennrich , M. J. Lang , A. Lamerato , S. LeBohec , G. Maier , S. McArthur , A. McCann , M. McCutcheon , P. Moriarty , R. Mukherjee , R. A. Ong , A. N. Otte , D. Pandel , J. S. Perkins , D. Petry , A. Pichel , M. Pohl , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , E. Roache , H. J. Rose , P. Roustazadeh , M. Schroedter , G. H. Sembroski , G. Demet Senturk , A. W. Smith , D. Steele , S. P. Swordy , G. Tešić , M. Theiling , S. Thibadeau , A. Varlotta , V. V. Vassiliev , S. Vincent , R. G. Wagner , S. P. Wakely , J. E. Ward , T. C. Weekes , A. Weinstein , T. Weisgarber , D. A. Williams , S. Wissel , M. Wood , B. Zitzer , M. Ackermann , M. Ajello , E. Antolini , L. Baldini , J. Ballet , G. Barbiellini , D. Bastieri , K. Bechtol , R. Bellazzini , B. Berenji , R. D. Blandford , E. D. Bloom , E. Bonamente , A. W. Borgland , A. Bouvier , J. Bregeon , M. Brigida , P. Bruel , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , P. A. Caraveo , S. Carrigan , J. M. Casandjian , E. Cavazzuti , C. Cecchi , Ö. Çelik , E. Charles , A. Chekhtman , C. C. Cheung , J. Chiang , S. Ciprini , R. Claus , J. Cohen-Tanugi , J. Conrad , C. D. Dermer , F. de Palma , E. do Couto e Silva , P. S. Drell , R. Dubois , D. Dumora , C. Farnier , C. Favuzzi , S. J. Fegan , P. Fortin , M. Frailis , Y. Fukazawa , S. Funk , P. Fusco , F. Gargano , D. Gasparrini , N. Gehrels , S. Germani , B. Giebels , N. Giglietto , F. Giordano , M. Giroletti , T. Glanzman , G. Godfrey , I. A. Grenier , J. E. Grove , S. Guiriec , E. Hays , D. Horan , R. E. Hughes , G. Jóhannesson , A. S. Johnson , W. N. Johnson , T. Kamae , H. Katagiri , J. Kataoka , J. Knödlseder , M. Kuss , J. Lande , L. Latronico , S. -H. Lee , M. Llena Garde , F. Longo , F. Loparco , B. Lott , M. N. Lovellette , P. Lubrano , A. Makeev , M. N. Mazziotta , P. F. Michelson , W. Mitthumsiri , T. Mizuno , A. A. Moiseev , C. Monte , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , P. L. Nolan , J. P. Norris , E. Nuss , M. Ohno , T. Ohsugi , N. Omodei , E. Orlando , J. F. Ormes , D. Paneque , J. H. Panetta , V. Pelassa , M. Pepe , M. Pesce-Rollins , F. Piron , T. A. Porter , S. Rainò , R. Rando , M. Razzano , A. Reimer , O. Reimer , J. Ripken , A. Y. Rodriguez , M. Roth , H. F. -W. Sadrozinski , D. Sanchez , A. Sander , J. D. Scargle , C. Sgrò , E. J. Siskind , P. D. Smith , G. Spandre , P. Spinelli , M. S. Strickman , D. J. Suson , H. Takahashi , T. Tanaka , J. B. Thayer , J. G. Thayer , D. J. Thompson , L. Tibaldo , D. F. Torres , G. Tosti , A. Tramacere , T. L. Usher , V. Vasileiou , N. Vilchez , V. Vitale , A. P. Waite , P. Wang , B. L. Winer , K. S. Wood , Z. Yang , T. Ylinen , M. Ziegler

Detection of Exceptional X-Ray Spectral Variability in the TeV BL Lac 1ES 2344+514

We present the results of six BeppoSAX observations of 1ES 2344+514, five of which were taken within a week. 1ES 2344+514, one of the few known TeV BL Lac objects, was detected by the BeppoSAX Narrow Field Instruments between 0.1 to \~50…

Astrophysics · Physics 2009-10-31 P. Giommi , P. Padovani , E. Perlman

Long term variability of the blazar PKS 2155-304

Time variability of the photon flux is a known feature of active galactic nuclei (AGN) and in particular of blazars. The high frequency peaked BL Lac (HBL) object PKS 2155-304 is one of the brightest sources in the TeV band and has been…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Jill Chevalier , Max Anton Kastendieck , Frank Rieger , Gilles Maurin , Jean-Philippe Lenain , Giovanni Lamanna

Multi-Wavelength Observations of the HBL Object 1ES 1011+496 in Spring 2008

In the spring of 2008 MAGIC organised multi-wavelength (MWL) observations of the blazar 1ES 1011+496. 1ES 1011+496 is a high-frequency peaked BL Lac object discovered at VHE gamma-rays by MAGIC in spring 2007 during an optical outburst…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Riho Reinthal , Stefan Rügamer , Elina J. Lindfors , Daniel Mazin , Antonio Stamerra , Francesco Longo , Fabrizio Lucarelli , Carlotta Pittori , Anne Lähteenmäki

Highlights from the VERITAS AGN Observation Program

VERITAS is one of the world's most sensitive detectors of astrophysical VHE (Very High Energy; E > 100 GeV) gamma rays. This array of four 12-m imaging atmospheric-Cherenkov telescopes has operated for ~10 years, and nearly 5000 hours of…

High Energy Astrophysical Phenomena · Physics 2017-09-13 Wystan Benbow , the VERITAS Collaboration

X-ray Flux and Spectral Variability of the TeV Blazars Mrk 421 and PKS 2155-304

We reviewed X-ray flux and spectral variability properties studied to date by various X-ray satellites for Mrk 421 and PKS 2155-304, which are TeV emitting blazars. Mrk 421 and PKS 2155-304 are the most X-ray luminous blazars in the…

High Energy Astrophysical Phenomena · Physics 2020-09-07 Alok C. Gupta

Observation of Strong Variability in the X-Ray Emission from Markarian 421 Correlated with the May 1996 TeV Flare

We observed the BL Lac object Markarian 421 with the X-ray satellite RXTE and the Whipple Air Cerenkov Telescope during a two week correlated X-ray/gamma-ray campaign in May 1996. Two dramatic outbursts with extremely rapid and strong flux…

Astrophysics · Physics 2009-10-30 Michael Schubnell

Multiwavelength study of TeV Blazar Mrk421 during giant flare

Context: The nearby (z=0.031) TeV blazar Mrk421 was reported to be in a high state of flux activity since November, 2009. Aims: To investigate possible changes in the physical parameters of Mrk421 during its high state of activity using…

High Energy Astrophysical Phenomena · Physics 2015-06-04 A. Shukla , V. R. Chitnis , P. R. Vishwanath , B. S. Acharya , G. C. Anupama , P. Bhattacharjee , R. J. Britto , T. P. Prabhu , L. Saha , B. B. Singh

A Very High Energy Gamma-Ray Spectrum of 1ES 2344+514

The BL Lacertae (BL Lac) object 1ES 2344+514 (1ES 2344), at a redshift of 0.044, was discovered as a source of very high energy (VHE) gamma rays by the Whipple Collaboration in 1995 \citep{2344Catanese98}. This detection was recently…

Astrophysics · Physics 2008-11-26 M. Schroedter , H. M. Badran , J. H. Buckley , J. Bussons Gordo , D. A. Carter-Lewis , C. Duke , D. J. Fegan , S. F. Fegan , J. P. Finley , G. H. Gillanders , J. Grube , D. Horan , G. E. Kenny , M. Kertzman , K. Kosack , F. Krennrich , D. B. Kieda , J. Kildea , M. J. Lang , Kuen Lee , P. Moriarty , J. Quinn , M. Quinn , G. B. Power-Mooney , H. Sembroski , S. P. Wakely , V. V. Vassiliev , T. C. Weekes , J. Zweerink

Observations of AGN with the First VERITAS Telescope

The first VERITAS (Very Energetic Radiation Imaging Telescope Array System) telescope has been in operation at the basecamp of the Whipple Observatory since January 2005. Here we present initial observations of AGN made using this…

Astrophysics · Physics 2019-08-14 P. Cogan

Searching for TeV Candidates in 4LAC High-synchrotron-peaked Frequency BL Lac Objects

The next generation of TeV detectors is expected to have a significantly enhanced performance. It is therefore constructive to search for new TeV candidates for observation. This paper focuses on TeV candidates among the…

High Energy Astrophysical Phenomena · Physics 2021-09-06 K. R. Zhu , S. J. Kang , R. X. Zhou , Y. G. Zheng

VHE Observations of BL Lacertae Objects: 1995-2000

The results of observations of 29 BL Lacertae objects taken with the Whipple Observatory 10 m gamma-ray Telescope between 1995 and 2000 are presented.

Astrophysics · Physics 2008-11-26 D. Horan

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

Simultaneous X-Ray and TeV Gamma-Ray Observations of the TeV Blazar Markarian 421 during February and May 2000

In this paper we present the results of simultaneous observations of the TeV blazar Markarian 421 (Mrk 421) at X-ray and TeV Gamma-ray energies with the Rossi X-Ray Timing Explorer (RXTE) and the stereoscopic Cherenkov Telescope system of…

Astrophysics · Physics 2009-11-06 H. Krawczynski , R. Sambruna , A. Kohnle , P. S. Coppi , The HEGRA Collaboration , F. Aharonian

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

VERITAS and Fermi-LAT observations of new HAWC sources

The HAWC (High Altitude Water Cherenkov) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100~GeV) gamma-ray sources based on 507 days of observation. Among these, there are nineteen sources that are…

High Energy Astrophysical Phenomena · Physics 2018-11-02 VERITAS Collaboration , A. U. Abeysekara , A. Archer , W. Benbow , R. Bird , R. Brose , M. Buchovecky , J. H. Buckley , V. Bugaev , A. J. Chromey , M. P. Connolly , W. Cui , M. K. Daniel , A. Falcone , Q. Feng , J. P. Finley , L. Fortson , A. Furniss , M. Hutten , D. Hanna , O. Hervet , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , M. Kertzman , D. Kieda , M. Krause , F. Krennrich , S. Kumar , 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 , I. Sushch , J. Tyler , S. P. Wakely , A. Weinstein , R. M. Wells , P. Wilcox , A. Wilhelm , D. A. Williams , T. J. Williamson , B. Zitzer , Fermi-LAT Collaboration , : , S. Abdollahi , M. Ajello , L. Baldini , G. Barbiellini , D. Bastieri , R. Bellazzini , B. Berenji , E. Bissaldi , R. D. Blandford , R. Bonino , E. Bottacini , T. J. Brandt , P. Bruel , R. Buehler , R. A. Cameron , R. Caputo , P. A. Caraveo , D. Castro , E. Cavazzuti , E. Charles , G. Chiaro , S. Ciprini , J. Cohen-Tanugi , D. Costantin , S. Cutini , F. D'Ammando , F. de Palma , N. Di Lalla , M. Di Mauro , L. Di Venere , A. Dominguez , C. Favuzzi , S. J. Fegan , A. Franckowiak , Y. Fukazawa , S. Funk , P. Fusco , F. Gargano , D. Gasparrini , N. Giglietto , F. Giordano , M. Giroletti , D. Green , I. A. Grenier , L. Guillemot , S. Guiriec , E. Hays , J. W. Hewitt , D. Horan , G. Johannesson , S. Kensei , M. Kuss , S. Larsson , L. Latronico , M. Lemoine-Goumard , J. Li , F. Longo , F. Loparco , M. N. Lovellette , P. Lubrano , J. D. Magill , S. Maldera , M. N. Mazziotta , J. E. McEnery , P. F. Michelson , W. Mitthumsiri , T. Mizuno , M. E. Monzani , A. Morselli , I. V. Moskalenko , M. Negro , E. Nuss , R. Ojha , N. Omodei , M. Orienti , E. Orlando , M. Palatiello , V. S. Paliya , D. Paneque , J. S. Perkins , M. Persic , M. Pesce-Rollins , V. Petrosian , F. Piron , T. A. Porter , G. Principe , S. Raino , R. Rando , B. Rani , M. Razzano , S. Razzaque , A. Reimer , O. Reimer , T. Reposeur , C. Sgro , E. J. Siskind , G. Spandre , P. Spinelli , D. J. Suson , H. Tajima , J. B. Thayer , D. J. Thompson , D. F. Torres , G. Tosti , E. Troja , J. Valverde , G. Vianello , M. Vogel , K. Wood , M. Yassine , HAWC Collaboration , : , R. Alfaro , C. Alvarez , J. D. Alvarez , R. Arceo , J. C. Arteaga-Velazquez , D. Avila Rojas , H. A. Ayala Solares , A. Becerril , E. Belmont-Moreno , S. Y. BenZvi , A. Bernal , J. Braun , C. Brisbois , K. S. Caballero-Mora , T. Capistran , A. Carraminana , S. Casanova , M. Castillo , U. Cotti , J. Cotzomi , S. Coutino de Leon , C. De Leon , E. De la Fuente , S. Dichiara , B. L. Dingus , M. A. DuVernois , J. C. Diaz-Velez , K. Engel , O. Enriquez-Rivera , D. W. Fiorino , H. Fleischhack , N. Fraija , J. A. Garcia-Gonzalez , F. Garfias , A. Gonzalez Munoz , M. M. Gonzalez , J. A. Goodman , Z. Hampel-Arias , J. P. Harding , S. Hernandez , A. Hernandez-Almada , B. Hona , F. Hueyotl-Zahuantitla , C. M. Hui , P. Huntemeyer , A. Iriarte , A. Jardin-Blicq , V. Joshi , S. Kaufmann , A. Lara , R. J. Lauer , W. H. Lee , D. Lennarz , H. Leon Vargas , J. T. Linnemann , A. L. Longinotti , G. Luis-Raya , R. Luna-Garcia , R. Lopez-Coto , K. Malone , S. S. Marinelli , O. Martinez , I. Martinez-Castellanos , J. Martinez-Castro , H. Martinez-Huerta , J. A. Matthews , P. Miranda-Romagnoli , E. Moreno , M. Mostafa , A. Nayerhoda , L. Nellen , M. Newbold , M. U. Nisa , R. Noriega-Papaqui , R. Pelayo , J. Pretz , E. G. Perez-Perez , Z. Ren , C. D. Rho , C. Riviere , D. Rosa-Gonzalez , M. Rosenberg , E. Ruiz-Velasco , H. Salazar , F. Salesa Greus , A. Sandoval , M. Schneider , M. Seglar Arroyo , G. Sinnis , A. J. Smith , R. W. Springer , P. Surajbali , I. Taboada , O. Tibolla , K. Tollefson , I. Torres , T. N. Ukwatta , L. Villasenor , T. Weisgarber , S. Westerhoff , I. G. Wisher , J. Wood , T. Yapici , G. Yodh , A. Zepeda , H. Zhou

Systematic search for VHE gamma-ray emission from X-ray bright high-frequency BL Lac objects

All but three (M87, BL Lac and 3C 279) extragalactic sources detected so far at very high energy (VHE) gamma-rays belong to the class of high-frequency peaked BL Lac (HBL) objects. This suggested to us a systematic scan of candidate sources…

Astrophysics · Physics 2019-08-12 M. Meyer

Observations of AGNs using PACT

We report our observations on 4 AGNs viz, Mkn421, Mkn501, 1ES1426+428 and ON231 belonging to a sub-class called blazars. The observations were carried out using the Pachmarhi Array of Cherenkov Telescopes and span about 6 years period from…

Astrophysics · Physics 2009-04-22 D. Bose , V. R. Chitnis , P. R. Vishwanath , P. Majumdar , M. A. Rahman , B. B. Singh , A. C. Gupta , B. S. Acharya

Multiwavelength modeling of TeV AGN observed by HESS

The High Energy Stereoscopic System (H.E.S.S.) experiment, a ground-based gamma-ray Cherenkov telescope array located in Namibia, has now detected many extragalactic objects, which redshifts range from z=0.00183 up to z=0.2, possibly more.…

Astrophysics · Physics 2007-09-12 Jean-Philippe Lenain

Multiwavelength observations and modeling of 1ES 1959+650 in a low flux state

We report on the VERITAS observations of the high-frequency peaked BL Lac object 1ES 1959+650 in the period 2007-2011. This source is detected at TeV energies by VERITAS at 16.4 standard deviation (sigma) significance in 7.6 hours of…

High Energy Astrophysical Phenomena · Physics 2013-08-30 VERITAS Collaboration , E. Aliu , S. Archambault , T. Arlen , T. Aune , M. Beilicke , W. Benbow , R. Bird , M. Boettcher , A. Bouvier , V. Bugaev , K. Byrum , A. Cesarini , L. Ciupik , E. Collins-Hughes , M. P. Connolly , W. Cui , R. Dickherber , C. Duke , J. Dumm , M. Errando , A. Falcone , S. Federici , Q. Feng , J. P. Finley , G. Finnegan , L. Fortson , A. Furniss , N. Galante , D. Gall , G. H. Gillanders , S. Griffin , J. Grube , G. Gyuk , D. Hanna , J. Holder , G. Hughes , T. B. Humensky , P. Kaaret , M. Kertzman , Y. Khassen , D. Kieda , H. Krawczynski , F. Krennrick , M. J. Lang , A. S. Madhavan , G. Maier , P. Majumdar , S. McArthur , A. McCann , P. Moriarty , R. Mukherjee , T. Nelson , A. O'Faolain de Bhroithe , R. A. Ong , M. Orr , A. N. Otte , N. Park , J. S. Perkins , A. Pichel , M. Pohl , A. Popkow , H. Prokoph , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , E. Roache , D. B. Saxon , M. Schroedter , G. H. Sembroski , C. Skole , A. W. Smith , D. Staszak , I. Telezhinsky , M. Theiling , J. Tyler , A. Varlotta , V. V. Vassiliev , S. P. Wakely , T. C. Weekes , A. Weinstein , R. Welsing , D. A. Williams , B. Zitzer