Related papers: Simultaneous multi-frequency observations of PG 15…

Multiwavelength Observations of the Blazar PKS~0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.2 degrees away from the best-fit position of the IceCube neutrino event 211208A. The source was in a high-flux state in the optical,…

High Energy Astrophysical Phenomena · Physics 2023-08-16 M. Pohl , K. Mori

Time-dependent modelling of PKS 2155-304 in a low state

We apply both leptonic and leptohadronic emission scenarios for modelling the multiwavelength photon spectra and the observed variability in the optical, X-ray, and TeV gamma-ray energy bands of blazar PKS 2155-304 while being in a low…

High Energy Astrophysical Phenomena · Physics 2014-11-19 Maria Petropoulou

A comprehensive view of PKS 2155-304 from 2008 to 2023 through a multi-epoch modeling of its spectral energy distributions

We present a detailed investigation of the temporal and spectral evolution of the emission from the blazar PKS 2155-304, a high-synchrotron-peaked (HSP) blazar. Using $\gamma$-ray, X-ray, optical/UV, and infrared data assembled from the…

High Energy Astrophysical Phenomena · Physics 2025-09-16 G. Harutyunyan , N. Sahakyan , D. Bégué , M. Khachatryan

Long-term multiwavelength observations of 1ES 1218+304: physical implications of the flux and spectral variability

This paper presents the results of a detailed timing and spectral analysis of the TeV-detected blazar 1ES 1218+304, focused on the observations performed with the different instruments onboard the Neil Gehrels Swift Observatory in the…

Astrophysics of Galaxies · Physics 2025-04-22 B. Kapanadze , A. Gurchumelia , M. Aller

Discovery of Very High Energy Gamma Rays from 1ES 1440+122

The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling 53 hours,…

High Energy Astrophysical Phenomena · Physics 2016-08-10 VERITAS Collaboration , S. Archambault , A. Archer , A. Barnacka , B. Behera , M. Beilicke , W. Benbow , K. Berger , R. Bird , M. Boettcher , J. H. Buckley , V. Bugaev , J. V Cardenzana , M. Cerruti , X. Chen , J. L. Christiansen , L. Ciupik , E. Collins-Hughes , M. P. Connolly , W. Cui , H. J. Dickinson , J. Dumm , J. D. Eisch , M. Errando , A. Falcone , S. Federici , Q. Feng , J. P. Finley , H. Fleischhack , L. Fortson , A. Furniss , G. H. Gillanders , S. Godambe , S. Griffin , S. T. Griffiths , J. Grube , G. Gyuk , N. Haakansson , D. Hanna , J. Holder , G. Hughes , C. A. Johnson , P. Kaaret , P. Kar , M. Kertzman , Y. Khassen , D. Kieda , H. Krawczynski , S. Kumar , M. J. Lang , A. S Madhavan , G. Maier , S. McArthur , A. McCann , K. Meagher , J. Millis , P. Moriarty , T. Nelson , D. Nieto , A. O'Faolain de Bhroithe , R. A. Ong , A. N. Otte , N. Park , J. S. Perkins , M. Pohl , A. Popkow , H. Prokoph , E. Pueschel , J. Quinn , K. Ragan , J. Rajotte , L. C. Reyes , P. T. Reynolds , G. T. Richards , E. Roache , G. H. Sembroski , K. Shahinyan , A. W. Smith , D. Staszak , K Sweeney , I. Telezhinsky , J. V. Tucci , J. Tyler , A. Varlotta , V. V. Vassiliev , S. P. Wakely , R. Welsing , A. Wilhelm , D. A. Williams , B. Zitzer

Simultaneous multi-wavelength observations of GRS 1915+105

We present the result of multi-wavelength observations of the microquasar GRS 1915+105 in a plateau state with a luminosity of ~7.5x10^{38) erg s-1 (~40% L_Edd), conducted simultaneously with the INTEGRAL and RXTE satellites, the ESO/NTT,…

Astrophysics · Physics 2009-11-10 Yael Fuchs , J. Rodriguez , I. F. Mirabel , S. Chaty , M. Ribo , V. Dhawan , P. Goldoni , P. Sizun , G. G. Pooley , A. A. Zdziarski , D. C. Hannikainen , P. Kretschmar , B. Cordier , N. Lund

Long term multi-wavelength view of the blazar 1ES 1218+304

In this work, we present a multi-wavelength study of the blazar 1ES 1218+304 using near simultaneous observations over 10 years during the period September 1, 2008 to August 31, 2018 (MJD 54710-58361). We have analyzed data from…

High Energy Astrophysical Phenomena · Physics 2019-09-25 K. K. Singh , B. Bisschoff , B. van Soelen , A. Tolamatti , J. P. Marais , P. J. Meintjes

AGILE detection of intense gamma-ray emission from the blazar PKS 1510-089

We report the detection by the AGILE (Astro-rivelatore Gamma a Immagini LEggero) satellite of an intense gamma-ray flare from the source AGL J1511-0909, associated with the powerful quasar PKS 1510-089, during ten days of observations from…

Astrophysics · Physics 2009-11-13 G. Pucella , V. Vittorini , F. D'Ammando , M. Tavani , C. M. Raiteri , M. Villata , A. Argan , G. Barbiellini , F. Boffelli , A. Bulgarelli , P. Caraveo , P. W. Cattaneo , A. W. Chen , V. Cocco , E. Costa , E. Del Monte , G. De Paris , G. Di Cocco , I. Donnarumma , Y. Evangelista , M. Feroci , M. Fiorini , T. Froysland , F. Fuschino , M. Galli , F. Gianotti , A. Giuliani , C. Labanti , I. Lapshov , F. Lazzarotto , P. Lipari , F. Longo , M. Marisaldi , S. Mereghetti , A. Morselli , L. Pacciani , A. Pellizzoni , F. Perotti , P. Picozza , M. Prest , M. Rapisarda , A. Rappoldi , P. Soffitta , M. Trifoglio , A. Trois , E. Vallazza , S. Vercellone , A. Zambra , D. Zanello , L. A. Antonelli , S. Colafrancesco , S. Cutini , D. Gasparrini , P. Giommi , C. Pittori , F. Verrecchia , L. Salotti , M. F. Aller , H. D. Aller , D. Carosati , V. M. Larionov , R. Ligustri

Evidence for Gamma-Ray Flares in 3C 279 and PKS 1622-297 at ~10 MeV

The EGRET experiment aboard the Compton Gamma-Ray Observatory (CGRO) has observed at energies above 100 MeV strong gamma-ray flares with short-term time variability from the gamma-ray blazars 3C 279 and PKS 1622-297. During these flaring…

Astrophysics · Physics 2009-10-30 W. Collmar , V. Schoenfelder , H. Bloemen , J. J. Blom , W. Hermsen , M. McConnell , J. G. Stacy , K. Bennett , O. R. Williams

Fermi LAT detection of extraordinary variability in the gamma-ray emission of the blazar PKS 1510-089

We have reanalyzed the giant outburst of the blazar PKS 1510-089 (z=0.36) that occurred on 2011 October-November. The gamma-ray flux in the 0.1-100 GeV energy range exceeded the value of 10^-5 ph/cm2/s for several days. The peak flux was…

High Energy Astrophysical Phenomena · Physics 2013-08-29 L. Foschini , G. Bonnoli , G. Ghisellini , G. Tagliaferri , F. Tavecchio , A. Stamerra

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

Models for the Spectral Energy Distributions and Variability of Blazars

In this review, recent progress in theoretical models for blazar emission will be summarized. The salient features of both leptonic and lepto-hadronic approaches to modeling blazar spectral energy distributions will be reviewed. I will…

High Energy Astrophysical Phenomena · Physics 2010-06-28 Markus Boettcher

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

Simultaneous Swift and REM monitoring of the blazar PKS0537-441 in 2005

The blazar PKS0537-441 has been observed by Swift between the end of 2004 and November 2005. The BAT monitored it recurrently for a total of 2.7 Ms, and the XRT and UVOT pointed it on seven occasions for a total of 67 ks, making it one of…

Astrophysics · Physics 2009-06-23 E. Pian , P. Romano , A. Treves , G. Ghisellini , S. Covino , A. Cucchiara , A. Dolcini , G. Tagliaferri , C. Markwardt , S. Campana , G. Chincarini , N. Gehrels , P. Giommi , L. Maraschi , S. D. Vergani , F. M. Zerbi , E. Molinari , V. Testa , G. Tosti , F. Vitali , L. A. Antonelli , P. Conconi , G. Malaspina , L. Nicastro , E. Palazzi , E. J. A. Meurs , L. Norci

A gamma-ray flare from TXS 1508+572: characterizing the jet of a $z=4.31$ blazar in the early Universe

Blazars can be detected from very large distances due to their high luminosity. However, the detection of $\gamma$-ray emission of blazars beyond $z=3$ has only been confirmed for a small number of sources. Such observations probe the…

High Energy Astrophysical Phenomena · Physics 2024-08-05 Andrea Gokus , Markus Böttcher , Manel Errando , Michael Kreter , Jonas Heßdörfer , Florian Eppel , Matthias Kadler , Paul S. Smith , Petra Benke , Leonid I. Gurvits , Alex Kraus , Mikhail Lisakov , Felicia McBride , Eduardo Ros , Florian Rösch , Jörn Wilms

New hard-TeV extreme blazars detected with the MAGIC telescopes

Extreme high-frequency peaked BL Lac objects (EHBLs) are blazars which exhibit extremely energetic synchrotron emission. They also feature non-thermal gamma-ray emission whose peak lies in the very high-energy (VHE, E > 100 GeV) range, and…

High Energy Astrophysical Phenomena · Physics 2020-08-21 MAGIC Collaboration , V. A. Acciari , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , K. Asano , 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 , R. Carosi , G. Ceribella , M. Cerruti , Y. Chai , A. Chilingaryan , S. Cikota , S. M. Colak , U. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , 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 , G. Ferrara , D. Fidalgo , L. Foffano , M. V. Fonseca , L. Font , C. Fruck , S. Fukami , 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 , 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 , S. Nozaki , S. Paiano , 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 , V. Vagelli , J. van Scherpenberg , G. Vanzo , M. Vazquez Acosta , C. F. Vigorito , V. Vitale , I. Vovk , M. Will , D. Zarić , C. Arcaro , A. Carosi , F. D'Ammando , F. Tombesi , A. Lohfink

Discovery of very-high-energy emission from RGB J2243+203 and derivation of its redshift upper limit

Very-high-energy (VHE; $>$ 100 GeV) gamma-ray emission from the blazar RGB J2243+203 was discovered with the VERITAS Cherenkov telescope array, during the period between 21 and 24 December 2014. The VERITAS energy spectrum from this source…

High Energy Astrophysical Phenomena · Physics 2017-11-15 A. U. Abeysekara , S. Archambault , A. Archer , W. Benbow , R. Bird , R. Brose , M. Buchovecky , J. H. Buckley , V. Bugaev , M. Cerruti , M. P. Connolly , W. Cui , A. Falcone , Q. Feng , J. P. Finley , H. Fleischhack , L. Fortson , A. Furniss , G. H. Gillanders , S. Griffin , J. Grube , M. Hutten , D. Hanna , O. Hervet , J. Holder , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , N. Kelley-Hoskins , M. Kertzman , D. Kieda , M. Krause , F. Krennrich , S. Kumar , M. J. Lang , G. Maier , S. McArthur , P. Moriarty , R. Mukherjee , D. Nieto , S. OBrien , R. A. Ong , A. N. Otte , N. Park , A. Petrashyk , M. Poh , A. Popkow , E. Puesche , J. Quinn , K. Ragan , P. T. Reynolds , G. T. Richards , E. Roache , C. Rulten , I. Sadeh , M. Santander , G. H. Sembroski , K. Shahinyan , D. Staszak , I. Telezhinsky , J. Tyler , V. V. Vassiliev , S. P. Wakely , O. M. Weiner , A. Weinstein , P. Wilcox , A. Wilhelm , D. A. Williams , B. Zitzer

MAGIC and Multi-Wavelength Observations of three HBLs in 2008

The high-frequency peaked blazars and known TeV emitters 1ES 1011+496, Mrk 180 and 1ES 2344+514 have been observed in the course of multi-wavelength campaigns in 2008, covering the frequency bands from radio up to TeV energies. For all…

High Energy Astrophysical Phenomena · Physics 2019-08-15 S. Rügamer , E. Angelakis , D. Bastieri , D. Dorner , Y. Y. Kovalev , A. Lähteenmäki , E. Lindfors , C. Pittori , R. Reinthal , K. V. Sokolovsky , A. Stamerra , H. Ungerechts

Monitoring of gamma-ray blazars with AGILE

Thanks to the wide field of view of its gamma-ray imager, the AGILE satellite obtained a long term monitoring of the brightest blazars in the sky and during the first 3 years of operation detected several blazars in a high gamma-ray state:…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Filippo D'Ammando

Understanding the nature of the blazar CGRaBS~J0211$+$1051

The source CGRaBS~J0211$+$1051 (MG1 J021114+1051, z=0.20) flared up on 2011 January 23 in high-energy $\gamma$-rays as reported by {\it Fermi}/LAT. This event was followed by the increased activity at the UV, optical and radio frequencies…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Sunil Chandra , Kiran S Baliyan , Shashikiran Ganesh , Luigi Foschini