Related papers: Degree-scale GeV "jets" from active and dead TeV b…

Extragalactic background light models and GeV-TeV observation of blazars

In this work, we use two different methods to determine the opacity of the TeV gamma-rays caused by the extragalactic background light (EBL) via e-e+ production due to photon-photon interaction. The first method, Model-Dependent Approach,…

High Energy Astrophysical Phenomena · Physics 2020-04-07 K. K. Singh , P. J. Meintjes

The Highest Energy Emission Detected by EGRET from Blazars

Published EGRET spectra from blazars extend only to 10 GeV, yet EGRET has detected approximately 2000 gamma-rays above 10 GeV of which about half are at high Galactic latitude. We report a search of these high-energy gamma-rays for…

Astrophysics · Physics 2009-11-06 Brenda L. Dingus , David L. Bertsch

The diffuse GeV-TeV $\gamma$-ray emission of the Cygnus region

Recently the Milagro experiment observed diffuse multi-TeV gamma-ray emission in the Cygnus region, which is significantly stronger than what predicted by the Galactic cosmic ray model. However, the sub-GeV observation by EGRET shows no…

Astrophysics · Physics 2009-06-23 Xiao-Jun Bi , Tian-Lu Chen , Yue Wang , Qiang Yuan

Search for GeV gamma-ray emission from the possible TeV-bright red dwarfs with Fermi-LAT

Red dwarfs have been suggested to be among the possible astrophysical species accelerating particles and emitting TeV $\gamma$-rays. As an effort to search for the GeV $\gamma$-ray counterparts of the suggested TeV emission from eight red…

High Energy Astrophysical Phenomena · Physics 2024-03-20 Chen Huang , Xiao Zhang , Yang Chen , Wen-Juan Zhong

Gamma-Ray Bursts at TeV Energies: Theoretical Considerations

Gamma-ray bursts (GRBs) are the most luminous explosions in the Universe and are powered by ultra-relativistic jets. Their prompt $\gamma$-ray emission briefly outshines the rest of the $\gamma$-ray sky making them detectable from…

High Energy Astrophysical Phenomena · Physics 2022-06-07 Ramandeep Gill , Jonathan Granot

Teraelectronvolt emission from the $\gamma$-ray burst GRB 190114C

Gamma-ray bursts (GRBs) of the long-duration class are the most luminous sources of electromagnetic radiation known in the Universe. They are generated by outflows of plasma ejected at near the speed of light by newly formed neutron stars…

High Energy Astrophysical Phenomena · Physics 2020-06-15 MAGIC Collaboration , V. A. Acciari , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , D. Baack , A. Babić , B. Banerjee , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , L. Bellizzi , E. Bernardini , A. Berti , J. Besenrieder , W. Bhattacharyya , C. Bigongiari , A. Biland , O. Blanch , G. Bonnoli , Ž. Bošnjak , G. Busetto , A. Carosi , R. Carosi , G. Ceribella , Y. Chai , A. Chilingaryan , S. Cikota , S. M. Colak , U. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , G. D'Amico , V. D'Elia , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , M. Delfino , J. Delgado , D. Depaoli , F. Di Pierro , L. Di Venere , E. Do Souto Espiñeira , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , D. Elsaesser , V. Fallah Ramazani , A. Fattorini , A. Fernández-Barral , G. Ferrara , D. Fidalgo , L. Foffano , M. V. Fonseca , L. Font , C. Fruck , S. Fukami , S. Gallozzi , R. J. García López , M. Garczarczyk , S. Gasparyan , M. Gaug , N. Giglietto , F. Giordano , N. Godinović , D. Green , D. Guberman , D. Hadasch , A. Hahn , J. Herrera , J. Hoang , D. Hrupec , M. Hütten , T. Inada , S. Inoue , K. Ishio , Y. Iwamura , L. Jouvin , D. Kerszberg , H. Kubo , J. Kushida , A. Lamastra , D. Lelas , F. Leone , E. Lindfors , S. Lombardi , F. Longo , M. López , R. López-Coto , A. López-Oramas , S. Loporchio , B. Machado de Oliveira Fraga , C. Maggio , P. Majumdar , M. Makariev , M. Mallamaci , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , M. Mariotti , M. Martínez , S. Masuda , D. Mazin , S. Mićanović , D. Miceli , M. Minev , J. M. Miranda , R. Mirzoyan , E. Molina , A. Moralejo , D. Morcuende , V. Moreno , E. Moretti , P. Munar-Adrover , V. Neustroev , C. Nigro , K. Nilsson , D. Ninci , K. Nishijima , K. Noda , L. Nogués , M. Nöthe , S. Nozaki , S. Paiano , J. Palacio , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , P. Peñil , M. Peresano , M. Persic , P. G. Prada Moroni , E. Prandini , I. Puljak , W. Rhode , M. Ribó , J. Rico , C. Righi , A. Rugliancich , L. Saha , N. Sahakyan , T. Saito , S. Sakurai , K. Satalecka , K. Schmidt , T. Schweizer , J. Sitarek , I. Šnidarić , D. Sobczynska , A. Somero , A. Stamerra , D. Strom , M. Strzys , Y. Suda , T. Surić , M. Takahashi , F. Tavecchio , P. Temnikov , T. Terzić , M. Teshima , N. Torres-Albà , L. Tosti , S. Tsujimoto , V. Vagelli , J. van Scherpenberg , G. Vanzo , M. Vazquez Acosta , C. F. Vigorito , V. Vitale , I. Vovk , M. Will , D. Zarić , L. Nava

TeV Gamma-Ray Sources from a Survey of the Galactic Plane with Milagro

A survey of Galactic gamma-ray sources at a median energy of ~20 TeV has been performed using the Milagro Gamma Ray Observatory. Eight candidate sources of TeV emission are detected with pre-trials significance $>4.5\sigma$ in the region of…

Astrophysics · Physics 2009-06-23 A. A. Abdo , B. Allen , D. Berley , S. Casanova , C. Chen , D. G. Coyne , B. L. Dingus , R. W. Ellsworth , L. Fleysher , R. Fleysher , M. M. Gonzalez , J. A. Goodman , E. Hays , C. M. Hoffman , B. Hopper , P. H. Huntemeyer , B. E. Kolterman , C. P. Lansdell , J. T. Linnemann , J. E. McEnery , A. I. Mincer , P. Nemethy , D. Noyes , J. M. Ryan , P. M. Saz Parkinson , A. Shoup , G. Sinnis , A. J. Smith , G. W. Sullivan , V. Vasileiou , G. P. Walker , D. A. Williams , X. W. Xu , G. B. Yodh

Is GeV Emission from Gamma-Ray Bursts of External Shock Origin?

Recent observations of Gamma-Ray Bursts (GRBs) by the Fermi Large Area Telescope (LAT) revealed a power law decay feature of the high energy emission (above 100 MeV), which led to the suggestion that it originates from a (probably…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Amanda Maxham , Bin-Bin Zhang , Bing Zhang

TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess

The Geminga pulsar has long been one of the most intriguing MeV-GeV gamma-ray point sources. We examine the implications of the recent Milagro detection of extended, multi-TeV gamma-ray emission from Geminga, finding that this reveals the…

Astrophysics · Physics 2010-04-21 Hasan Yuksel , Matthew D. Kistler , Todor Stanev

A method of measurement of extragalactic magnetic fields by TeV gamma ray telescopes

We propose a method of measurement of extragalactic magnetic fields in observations of TeV gamma-rays from distant blazars. Multi-TeV gamma-rays are emitted by these sources in narrow jet with opening angle of few degrees. These primary…

Astrophysics · Physics 2008-11-26 A. Neronov , D. V. Semikoz

A lower bound on intergalactic magnetic fields from time variability of 1ES 0229+200 from MAGIC and Fermi/LAT observations

Extended and delayed emission around distant TeV sources induced by the effects of propagation of gamma rays through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). We search for delayed…

High Energy Astrophysical Phenomena · Physics 2023-02-22 MAGIC Collaboration , V. A. Acciari , I. Agudo , T. Aniello , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , M. Artero , K. Asano , D. Baack , A. Babić , A. Baquero , U. Barres de Almeida , J. A. Barrio , I. Batković , J. Becerra González , W. Bednarek , E. Bernardini , M. Bernardos , A. Berti , J. Besenrieder , W. Bhattacharyya , C. Bigongiari , A. Biland , O. Blanch , H. Bökenkamp , G. Bonnoli , Ž. Bošnjak , I. Burelli , G. Busetto , R. Carosi , G. Ceribella , M. Cerruti , Y. Chai , A. Chilingarian , S. Cikota , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , G. D'Amico , V. D'Elia , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , A. Del Popolo , M. Delfino , J. Delgado , C. Delgado Mendez , D. Depaoli , F. Di Pierro , L. Di Venere , E. Do Souto Espiñeira , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , D. Elsaesser , V. Fallah Ramazani , L. Fariña , A. Fattorini , L. Font , C. Fruck , S. Fukami , Y. Fukazawa , R. J. García López , M. Garczarczyk , S. Gasparyan , M. Gaug , N. Giglietto , F. Giordano , P. Gliwny , N. Godinović , J. G. Green , D. Green , D. Hadasch , A. Hahn , T. Hassan , L. Heckmann , J. Herrera , D. Hrupec , M. Hütten , T. Inada , R. Iotov , K. Ishio , Y. Iwamura , I. Jiménez Martínez , J. Jormanainen , L. Jouvin , D. Kerszberg , Y. Kobayashi , H. Kubo , J. Kushida , A. Lamastra , D. Lelas , F. Leone , E. Lindfors , L. Linhoff , I. Liodakis , S. Lombardi , F. Longo , R. López-Coto , M. López-Moya , A. López-Oramas , S. Loporchio , A. Lorini , B. Machado de Oliveira Fraga , C. Maggio , P. Majumdar , M. Makariev , M. Mallamaci , G. Maneva , M. Manganaro , K. Mannheim , M. Mariotti , M. Martínez , A. Mas Aguilar , D. Mazin , S. Menchiari , S. Mender , S. Mićanović , D. Miceli , T. Miener , J. M. Miranda , R. Mirzoyan , E. Molina , H. A. Mondal , A. Moralejo , D. Morcuende , V. Moreno , E. Moretti , T. Nakamori , C. Nanci , L. Nava , V. Neustroev , M. Nievas Rosillo , C. Nigro , K. Nilsson , K. Nishijima , K. Noda , S. Nozaki , Y. Ohtani , T. Oka , J. Otero-Santos , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , L. Pavletić , P. Peñil , M. Persic , M. Pihet , P. G. Prada Moroni , E. Prandini , C. Priyadarshi , I. Puljak , W. Rhode , M. Ribó , J. Rico , C. Righi , A. Rugliancich , N. Sahakyan , T. Saito , S. Sakurai , K. Satalecka , F. G. Saturni , B. Schleicher , K. Schmidt , F. Schmuckermaier , J. L. Schubert , T. Schweizer , J. Sitarek , I. Šnidarić , D. Sobczynska , A. Spolon , A. Stamerra , J. Strišković , D. Strom , M. Strzys , Y. Suda , T. Surić , M. Takahashi , R. Takeishi , F. Tavecchio , P. Temnikov , T. Terzić , M. Teshima , L. Tosti , S. Truzzi , A. Tutone , S. Ubach , J. van Scherpenberg , G. Vanzo , M. Vazquez Acosta , S. Ventura , V. Verguilov , I. Viale , C. F. Vigorito , V. Vitale , I. Vovk , M. Will , C. Wunderlich , T. Yamamoto , D. Zarić , A. Neronov , D. Semikoz , A. Korochkin

Multi-TeV flaring from high energy blazars: An evidence of the photohadronic process

The high energy peaked blazars are known to undergo episodes of flaring in GeV-TeV gamma-rays involving different time scales and the flaring mechanism is not well understood despite long term simultaneous multiwavelength observations.…

High Energy Astrophysical Phenomena · Physics 2019-10-16 Sarira Sahu , Carlos E. Lopez Fortin , Shigehiro Nagataki

Probing the gamma-ray emission from HESS J1834-087 using H.E.S.S. and Fermi LAT observations

Previous observations with HESS have revealed the existence of an extended very-high-energy (VHE; E>100 GeV) gamma-ray source, HESS J1834-087, coincident with the SNR W41. The origin of the gamma-ray emission has been further investigated…

High Energy Astrophysical Phenomena · Physics 2015-06-22 The H. E. S. S. Collaboration , : , A. Abramowski , F. Aharonian , F. Ait Benkhali , A. G. Akhperjanian , E. Angüner , G. Anton , M. Backes , S. Balenderan , A. Balzer , A. Barnacka , Y. Becherini , J. Becker Tjus , 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 , P. M. Chadwick , R. Chalme-Calvet , R. C. G. Chaves , A. Cheesebrough , M. Chrétien , S. Colafrancesco , G. Cologna , J. Conrad , C. Couturier , Y. Cui , 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 , G. Giavitto , B. Giebels , J. F. Glicenstein , M. -H. Grondin , M. Grudzińska , 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. 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 , 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 , R. Moderski , M. Mohamed , E. Moulin , T. Murach , C. L. Naumann , M. de Naurois , J. Niemiec , S. J. Nolan , L. Oakes , H. Odaka , 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 , 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. A. Sanchez , A. Santangelo , R. Schlickeiser , F. Schüssler , A. Schulz , U. Schwanke , S. Schwarzburg , S. Schwemmer , H. Sol , 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 , C. Venter , A. Viana , P. Vincent , H. J. Völk , F. Volpe , M. Vorster , T. Vuillaume , S. J. Wagner , 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 , M. Zacharias , A. A. Zdziarski , A. Zech , H. -S. Zechlin , Fermi-LAT Collaboration , F. Acero , J. M. Casandjian , J. Cohen-Tanugi , F. Giordano , L. Guillemot , J. Lande , H. Pletsch , Y. Uchiyama

The extragalactic background light, the Hubble constant, and anomalies: conclusions from 20 years of TeV gamma-ray observations

Ground-based observatories have been collecting 0.2 - 20 TeV gamma rays from blazars for about twenty years. These gamma rays can experience absorption along the line of sight due to interactions with the extragalactic background light…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-14 Jonathan Biteau , David A. Williams

Gamma-Ray Observational Properties of TeV-Detected Blazars

The synergy between the Fermi-LAT and ground-based Cherenkov telescope arrays gives us the opportunity for the first time to characterize the high-energy emission from blazars over 5 decades in energy, from 100 MeV to 10 TeV. In this study,…

High Energy Astrophysical Phenomena · Physics 2015-06-12 G. D. Senturk , M. Errando , M. Boettcher , R. Mukherjee

Study of optical and gamma-ray long-term variability in blazars

Blazars, a subset of powerful active galactic nuclei, feature relativistic jets that shine in a broadband electromagnetic radiation, e. g. from radio to TeV emission. Here I present the results of the studies that explore gamma-ray and…

High Energy Astrophysical Phenomena · Physics 2022-10-18 Gopal Bhatta

TeV Observations of the Galactic Plane with HAWC and Joint Analysis of GeV Data from Fermi

A number of Galactic sources emit GeV-TeV gamma rays that are produced through leptonic and/or hadronic mechanisms. Spectral analysis in this energy range is crucial in order to understand the emission mechanisms. The HAWC Gamma-Ray…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Hao Zhou , C. Michelle Hui , Petra Huentemeyer

Diffuse Emission from the Galactic Plane and Unidentified EGRET Sources

Diffuse Galactic gamma-ray emission is produced in interactions of cosmic rays with gas and ambient photon fields and thus provides us with an indirect measurement of cosmic rays in various locations in the Galaxy. The diffuse gamma-ray…

Astrophysics · Physics 2007-05-23 Martin Pohl

GeV-TeV Connections in Galaxies: Evolutionary Signatures from Pulsars in Globular Clusters

The dominant mechanisms underlying high-energy $\gamma$-ray emission from galaxies vary by galaxy type. In starbursts, a major contribution comes from neutral pion decay. This is driven by interactions between interstellar gas and hadronic…

High Energy Astrophysical Phenomena · Physics 2025-08-26 Ellis R. Owen , Yoshiyuki Inoue , Chung-Yue Hui , Tatsuki Fujiwara , Albert K. H. Kong

Bright blazar flares with CTA

The TeV extragalactic sky is dominated by blazars, radio-loud active galactic nuclei with a relativistic jet pointing towards the Earth. Blazars show variability that can be quite exceptional both in terms of flux (orders of magnitude of…

High Energy Astrophysical Phenomena · Physics 2023-09-19 M. Cerruti , J. Finke , G. Grolleron , J. P. Lenain , T. Hovatta , M. Joshi , E. Lindfors , P. Morris , M. Petropoulou , P. Romano , S. Vercellone , M. Zacharias