Related papers: Target of Opportunity observations of blazars with…

Target of Opportunity Observations of Blazars with H.E.S.S

The very-high-energy (VHE, E>100 GeV) extragalactic sky is dominated by blazars, a class of active galactic nuclei which show rapid variability at all wavelengths. Target of Opportunity (ToO) observations triggered by flaring activity…

High Energy Astrophysical Phenomena · Physics 2017-10-24 F. Schüssler , M. Seglar-Arroyo , M. Arrieta , M. Böttcher , C. Boisson , M. Cerruti , N. Chakraborty , I. D. Davids , F. Jankowsky , J. P. Lenain , H. Prokoph , D. Sanchez , S. Wagner , M. Zacharias , A. Zech , the H. E. S. S. Collaboration

Target of Opportunity observations of flaring blazars with H.E.S.S.$\ $

Blazars are the most common class of TeV extragalactic emitters. In the framework of the AGN unified model, they are understood as AGNs with a relativistic jet pointing close the line of sight. They are characterized by extreme variability,…

High Energy Astrophysical Phenomena · Physics 2023-09-19 M. Cerruti , C. Boisson , M. Böttcher , O. Chibueze , I. Davids , A. Dmytriiev , G. Grolleron , F. Jankowsky , J. P. Lenain , A. Luashvili , M. Zacharias

H.E.S.S. observations of very-high-energy emission from 1RXS J023832.6-311658

Observations of the HBL blazar 1RXS J023832.6-311658 were made in 2013, 2015 and 2016 with the High Energy Stereoscopic System (H.E.S.S.). An excess of very high energy (VHE: > 100 GeV) gamma rays is clearly observed. The spectral energy…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Florian Gaté

H.E.S.S. discovery of very-high-energy gamma-ray emission of PKS 1440-389

Blazars are the most abundant class of known extragalactic very-high-energy (VHE, E>100 GeV) gamma-ray sources. However, one of the biggest difficulties in investigating their VHE emission resides in their limited number, since less than 60…

High Energy Astrophysical Phenomena · Physics 2019-08-14 H. Prokoph , Y. Becherini , M. Böttcher , C. Boisson , J. -P. Lenain , I. Sushch

H.E.S.S. detection and multi-wavelength study of the $z \sim$ 1 blazar PKS 0346$-$27

PKS 0346-27 is a Low Synchrotron Peaked (LSP) blazar at redshift 0.991. The very-high-energy (VHE, E > 100 GeV) spectra of blazars are always affected by $\gamma\gamma$ absorption by the Extragalactic Background Light (EBL) and…

High Energy Astrophysical Phenomena · Physics 2026-02-18 H. E. S. S. collaboration

Recent H.E.S.S. results on extra-galactic sources

Since the beginning of scientific operations in 2003, more than 20 extra-galactic sources have been detected with H.E.S.S. (High Energy Stereoscopic System) at very high energies (VHE): apart from the starburst galaxy NGC 253, all of them…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Matteo Cerruti

H.E.S.S. discovery of very-high-energy emission from the blazar PKS 0736+017: on the location of the $\gamma$-ray emitting region in FSRQs

With the installation of a new 28-m diameter imaging atmospheric Cherenkov telescope in the middle of the array, the H.E.S.S. instrument has entered since 2012 into its Phase II. The fifth large-size telescope is particularly important to…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Matteo Cerruti , Jean-Philippe Lenain , Heike Prokoph

Active Galaxies Studied with the H.E.S.S. Observatory

X-ray selected BL Lac objects dominate the population of extragalactic sources detected in the very high energy (VHE; photon energies >100GeV) gamma-ray regime with ground-based Cherenkov Telescopes. These are not the only extragalactic VHE…

High Energy Astrophysical Phenomena · Physics 2019-08-14 L. Stawarz

H.E.S.S. detection of very-high-energy gamma-ray emission from the quasar PKS 0736+017

Flat-spectrum radio-quasars (FSRQs) are rarely detected at very-high-energies (VHE; E>100 GeV) due to their low-frequency-peaked SEDs. At present, only 6 FSRQs are known to emit VHE photons, representing only 7% of the VHE extragalactic…

High Energy Astrophysical Phenomena · Physics 2020-01-29 H. E. S. S. Collaboration , : , H. Abdalla , R. Adam , F. Aharonian , F. Ait Benkhali , E. O. Angüner , M. Arakawa , C. Arcaro , C. Armand , H. Ashkar , M. Backes , V. Barbosa Martins , M. Barnard , Y. Becherini , D. Berge , K. Bernlöhr , R. Blackwell , M. Böttcher , C. Boisson , J. Bolmont , S. Bonnefoy , J. Bregeon , M. Breuhaus , F. Brun , P. Brun , M. Bryan , M. Büchele , T. Bulik , T. Bylund , M. Capasso , S. Caroff , A. Carosi , S. Casanova , M. Cerruti , T. Chand , S. Chandra , A. Chen , S. Colafrancesco , M. Curylo , I. D. Davids , C. Deil , J. Devin , P. deWilt , L. Dirson , A. Djannati-Ataï , A. Dmytriiev , A. Donath , V. Doroshenko , L. O'C. Drury , J. Dyks , K. Egberts , G. Emery , J. -P. Ernenwein , S. Eschbach , K. Feijen , S. Fegan , A. Fiasson , G. Fontaine , S. Funk , M. Füßling , S. Gabici , Y. A. Gallant , F. Gaté , G. Giavitto , D. Glawion , J. F. Glicenstein , D. Gottschall , M. -H. Grondin , J. Hahn , M. Haupt , G. Heinzelmann , G. Henri , G. Hermann , J. A. Hinton , W. Hofmann , C. Hoischen , T. L. Holch , M. Holler , D. Horns , D. Huber , H. Iwasaki , M. Jamrozy , D. Jankowsky , F. Jankowsky , A. Jardin-Blicq , I. Jung-Richardt , M. A. Kastendieck , K. Katarzynski , M. Katsuragawa , U. Katz , D. Khangulyan , B. Khélifi , J. King , S. Klepser , W. Kluzniak , Nu. Komin , K. Kosack , D. Kostunin , M. Kraus , G. Lamanna , J. Lau , A. Lemière , M. Lemoine-Goumard , J. -P. Lenain , E. Leser , C. Levy , T. Lohse , I. Lypova , J. Mackey , J. Majumdar , D. Malyshev , V. Marandon , A. Marcowith , A. Mares , C. Mariaud , G. Martí-Devesa , R. Marx , G. Maurin , P. J. Meintjes , A. M. W. Mitchell , R. Moderski , M. Mohamed , L. Mohrmann , J. Muller , C. Moore , E. Moulin , T. Murach , S. Nakashima , M. de Naurois , H. Ndiyavala , F. Niederwanger , J. Niemiec , L. Oakes , P. O'Brien , H. Odaka , S. Ohm , E. de Oña Wilhelmi , M. Ostrowski , I. Oya , M. Panter , R. D. Parsons , C. Perennes , P. -O. Petrucci , B. Peyaud , Q. Piel , S. Pita , V. Poireau , A. Priyana Noel , D. A. Prokhorov , H. Prokoph , G. Pühlhofer , M. Punch , A. Quirrenbach , S. Raab , R. Rauth , A. Reimer , O. Reimer , Q. Remy , M. Renaud , F. Rieger , L. Rinchiuso , C. Romoli , G. Rowell , B. Rudak , E. Ruiz-Velasco , V. Sahakian , S. Saito , D. A. Sanchez , A. Santangelo , M. Sasaki , R. Schlickeiser , F. Schüssler , A. Schulz , H. Schutte , U. Schwanke , S. Schwemmer , M. Seglar-Arroyo , M. Senniappan , A. S. Seyffert , N. Shafi , K. Shiningayamwe , R. Simoni , A. Sinha , H. Sol , A. Specovius , M. Spir-Jacob , L. Stawarz , R. Steenkamp , C. Stegmann , C. Steppa , T. Takahashi , T. Tavernier , A. M. Taylor , R. Terrier , D. Tiziani , M. Tluczykont , C. Trichard , M. Tsirou , N. Tsuji , R. Tuffs , Y. Uchiyama , D. J. van der Walt , C. van Eldik , C. van Rensburg , B. van Soelen , G. Vasileiadis , J. Veh , C. Venter , P. Vincent , J. Vink , F. Voisin , H. J. Völk , T. Vuillaume , Z. Wadiasingh , S. J. Wagner , R. White , A. Wierzcholska , R. Yang , H. Yoneda , M. Zacharias , R. Zanin , A. A. Zdziarski , A. Zech , A. Ziegler , J. Zorn , N. Zywucka , P. S. Smith

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

H.E.S.S. discovery of VHE gamma-rays from the quasar PKS 1510-089

The quasar PKS 1510-089 (z=0.361) was observed with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes during high states in the optical and GeV bands, to search for very high energy (VHE, defined as E >= 0.1 TeV) emission. VHE…

High Energy Astrophysical Phenomena · Physics 2013-05-01 H. E. S. S. Collaboration , A. Abramowski , F. Acero , F. Aharonian , A. G. Akhperjanian , G. Anton , S. Balenderan , A. Balzer , A. Barnacka , Y. Becherini , J. Becker Tjus , B. Behera , K. Bernlöhr , E. Birsin , J. Biteau , A. Bochow , C. Boisson , J. Bolmont , P. Bordas , J. Brucker , F. Brun , P. Brun , T. Bulik , S. Carrigan , S. Casanova , M. Cerruti , P. M. Chadwick , R. C. G. Chaves , A. Cheesebrough , 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 , K. Egberts , P. Eger , P. Espigat , L. Fallon , 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 , H. Gast , B. Giebels , J. F. Glicenstein , B. Glück , D. Göring , M. -H. Grondin , M. Grudzińska , S. Häffner , J. D. Hague , J. Hahn , D. Hampf , J. Harris , M. Hauser , S. Heinz , G. Heinzelmann , G. Henri , G. Hermann , A. Hillert , J. A. Hinton , W. Hofmann , P. Hofverberg , M. Holler , D. Horns , A. Jacholkowska , C. Jahn , M. Jamrozy , I. Jung , M. A. Kastendieck , K. Katarzynski , U. Katz , S. Kaufmann , B. Khélifi , S. Klepser , D. Klochkov , W. Kluźniak , T. Kneiske , D. Kolitzus , Nu. Komin , K. Kosack , R. Kossakowski , 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 , J. Masbou , G. Maurin , N. Maxted , M. Mayer , T. J. L. McComb , M. C. Medina , J. Méhault , U. Menzler , R. Moderski , M. Mohamed , E. Moulin , C. L. Naumann , M. Naumann-Godo , M. de Naurois , D. Nedbal , N. Nguyen , J. Niemiec , S. J. Nolan , S. Ohm , E. de Ona 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 , G. Pühlhofer , M. Punch , A. Quirrenbach , S. Raab , M. Raue , 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 , V. Sahakian , D. A. Sanchez , A. Santangelo , R. Schlickeiser , A. Schulz , U. Schwanke , S. Schwarzburg , S. Schwemmer , F. Sheidaei , J. L. Skilton , H. Sol , G. Spengler , Ł. 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 , S. Vorobiov , M. Vorster , S. J. Wagner , M. Ward , R. White , A. Wierzcholska , D. Wouters , M. Zacharias , A. Zajczyk , A. A. Zdziarski , A. Zech , H. -S. Zechlin

Study of the long-term Very High Energy emission of the blazars 1ES 1215+3031 and VER J0521+211 with the HAWC gamma-ray observatory

Blazars are the most abundant type of extragalactic gamma-ray source, usually presenting high variability across the electromagnetic spectrum. Their Very High Energy (VHE, above 0.1 TeV) emission has been studied in detail using Air…

High Energy Astrophysical Phenomena · Physics 2023-10-05 Fernando Ureña-Mena , Alberto Carramiñana , Anna Lia Longinotti , Daniel Rosa-González , HAWC Collaboration

The H.E.S.S. extragalactic sky survey with the first decade of observations

The results of the first extragalactic gamma-ray survey by the High Energy Stereoscopic System (H.E.S.S.) are presented. The survey comprises 2720 hours of very high-energy gamma-ray observations of the extragalactic sky, recorded with…

High Energy Astrophysical Phenomena · Physics 2025-05-01 H. E. S. S. Collaboration , F. Aharonian , F. Ait Benkhali , J. Aschersleben , H. Ashkar , M. Backes , V. Barbosa Martins , R. Batzofin , Y. Becherini , D. Berge , K. Bernlöhr , M. Böttcher , C. Boisson , J. Bolmont , M. de Bony de Lavergne , J. Borowska , M. Bouyahiaoui , F. Bradascio , R. Brose , A. Brown , F. Brun , B. Bruno , T. Bulik , C. Burger-Scheidlin , T. Bylund , S. Casanova , J. Celic , M. Cerruti , T. Chand , S. Chandra , A. Chen , J. Chibueze , O. Chibueze , G. Cotter , P. Cristofari , J. Damascene Mbarubucyeye , I. D. Davids , J. Devin , J. Djuvsland , A. Dmytriiev , K. Egberts , S. Einecke , S. Fegan , G. Fontaine , S. Funk , S. Gabici , J. F. Glicenstein , J. Glombitza , P. Goswami , G. Grolleron , L. Haerer , B. Heß , J. A. Hinton , W. Hofmann , T. L. Holch , M. Holler , D. Horns , Zhiqiu Huang , M. Jamrozy , F. Jankowsky , A. Jardin-Blicq , E. Kasai , K. Katarzyński , R. Khatoon , B. Khélifi , Nu. Komin , K. Kosack , D. Kostunin , A. Kundu , R. G. Lang , S. Le Stum , A. Lemière , M. Lemoine-Goumard , J. -P. Lenain , F. Leuschner , A. Luashvili , J. Mackey , D. Malyshev , V. Marandon , G. Martí-Devesa , R. Marx , A. Mehta , A. Mitchell , R. Moderski , L. Mohrmann , A. Montanari , M. de Naurois , J. Niemiec , P. O'Brien , L. Olivera-Nieto , E. de Ona Wilhelmi , M. Ostrowski , S. Panny , M. Panter , U. Pensec , G. Pühlhofer , M. Punch , A. Quirrenbach , S. Ravikularaman , M. Regeard , A. Reimer , O. Reimer , I. Reis , H. Ren , B. Reville , F. Rieger , G. Rowell , B. Rudak , E. Ruiz-Velasco , V. Sahakian , H. Salzmann , D. A. Sanchez , A. Santangelo , M. Sasaki , J. Schäfer , F. Schüssler , J. N. S. Shapopi , A. Sharma , H. Sol , S. Spencer , Ł. Stawarz , R. Steenkamp , S. Steinmassl , C. Steppa , H. Suzuki , T. Takahashi , T. Tanaka , A. M. Taylor , R. Terrier , A. Thakur , M. Tsirou , C. van Eldik , M. Vecchi , C. Venter , J. Vink , H. J. Völk , T. Wach , S. J. Wagner , A. Wierzcholska , M. Zacharias , A. A. Zdziarski , A. Zech , N. Żywucka

Monitoring the Extragalactic High Energy Sky

Blazars are jetted active galactic nuclei with a jet pointing close to the line of sight, hence enhancing their intrinsic luminosity and variability. Monitoring these sources is essential in order to catch them flaring and promptly organize…

High Energy Astrophysical Phenomena · Physics 2019-01-23 Jean-Philippe Lenain

Revisiting the TeV flare of PKS 2155-304 in 2006

Blazars, a subclass of active galactic nuclei (AGN), are known to be bright $\gamma$-ray sources, frequently exhibiting active (flaring) periods. The blazar PKS~2155-304 is a high synchrotron-peaked BL Lac object located at redshift…

High Energy Astrophysical Phenomena · Physics 2024-02-26 Hong-Bin Tan , Ruo-Yu Liu , Markus Böttcher

Very-high-energy blazars: updates from VERITAS observations and multi-wavelength campaigns

VERITAS is an array of four 12-m atmospheric Cherenkov telescopes, designed to observe the very-high-energy (VHE; E $\geq$100 GeV) sky. Since 2007, it has detected more than 20 extra-galactic sources, the majority of which are…

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

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

Discovery of very high energy gamma-ray emission from the blazar 1ES 0033+595 by the MAGIC telescopes

The number of known very high energy (VHE) blazars is $\sim\,50$, which is very small in comparison to the number of blazars detected in other frequencies. This situation is a handicap for population studies of blazars, which emit about…

High Energy Astrophysical Phenomena · Physics 2015-06-23 J. Aleksić , S. Ansoldi , L. A. Antonelli , P. Antoranz , A. Babic , P. Bangale , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , K. Berger , E. Bernardini , A. Biland , O. Blanch , S. Bonnefoy , G. Bonnoli , F. Borracci , T. Bretz , E. Carmona , A. Carosi , D. Carreto Fidalgo , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Da Vela , F. Dazzi , A. De Angelis , G. De Caneva , B. De Lotto , C. Delgado Mendez , M. Doert , A. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Eisenacher , D. Elsaesser , E. Farina , D. Ferenc , M. V. Fonseca , L. Font , K. Frantzen , C. Fruck , R. J. García López , M. Garczarczyk , D. Garrido Terrats , M. Gaug , N. Godinović , A. González Muñoz , S. R. Gozzini , D. Hadasch , M. Hayashida , J. Herrera , A. Herrero , D. Hildebrand , J. Hose , D. Hrupec , W. Idec , V. Kadenius , H. Kellermann , K. Kodani , Y. Konno , J. Krause , H. Kubo , J. Kushida , A. La Barbera , D. Lelas , N. Lewandowska , E. Lindfors , S. Lombardi , M. López , R. López-Coto , A. López-Oramas , E. Lorenz , I. Lozano , M. Makariev , K. Mallot , G. Maneva , N. Mankuzhiyil , K. Mannheim , L. Maraschi , B. Marcote , M. Mariotti , M. Martínez , D. Mazin , U. Menzel , M. Meucci , J. M. Miranda , R. Mirzoyan , A. Moralejo , P. Munar-Adrover , D. Nakajima , A. Niedzwiecki , K. Nilsson , K. Nishijima , K. Noda , N. Nowak , R. Orito , A. Overkemping , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , X. Paredes-Fortuny , S. Partini , M. Persic , F. Prada , P. G. Prada Moroni , E. Prandini , S. Preziuso , I. Puljak , R. Reinthal , W. Rhode , M. Ribó , J. Rico , J. Rodriguez Garcia , S. Rügamer , A. Saggion , T. Saito , K. Saito , K. Satalecka , V. Scalzotto , V. Scapin , C. Schultz , T. Schweizer , S. N. Shore , A. Sillanpää , J. Sitarek , I. Snidaric , D. Sobczynska , F. Spanier , V. Stamatescu , A. Stamerra , T. Steinbring , J. Storz , S. Sun , T. Surić , L. Takalo , H. Takami , F. Tavecchio , P. Temnikov , T. Terzić , D. Tescaro , M. Teshima , J. Thaele , O. Tibolla , D. F. Torres , T. Toyama , A. Treves , M. Uellenbeck , P. Vogler , R. M. Wagner , F. Zandanel , R. Zanin , V. Tronconi , S. Buson

Discovery of VHE emission from PKS 0447-439 with H.E.S.S. and MWL studies

Very-high energy (VHE) emission has been detected from PKS 0447-439 with the H.E.S.S. Cherenkov telescope array. This blazar is one of the brightest hard-spectrum extragalactic objects in the Fermi bright source list. Its detection with…

High Energy Astrophysical Phenomena · Physics 2011-05-05 A. Zech , B. Behera , Y. Becherini , C. Boisson , B. Giebels , M. Hauser , M. Kastendieck , S. Kaufmann , K. Kosack , J. -P. Lenain , M. de Naurois , M. Punch , M. Raue , H. Sol , S. Wagner , the H. E. S. S. collaboration

Spectro-Polarimetric Observations of TeV Sources (SPOTS): First results

Blazars are jetted active galactic nuclei, with the jet aligned along the observer's line of sight. Their spectral energy distributions are dominated by non-thermal emission, with an underlying thermal component at optical/ultraviolet…

High Energy Astrophysical Phenomena · Physics 2026-05-07 J. Barnard , B. van Soelen , I. P. van der Westhuizen , M. Böttcher , A. Martin-Carrillo , H. M. Schutte , S. van der Merwe , M. Zacharias