Related papers: Extreme blazars

Correlation between the TeV and X-ray emission in high--energy peaked BL Lac objects

We discuss the correlation between the evolution of the TeV emission and X-ray radiation observed in high-energy peaked BL Lac objects. We describe such a correlation by a simple power law. In the first part of this work we present…

Astrophysics · Physics 2009-11-10 K. Katarzynski , G. Ghisellini , F. Tavecchio , L. Maraschi , G. Fossati , A. Mastichiadis

Ultrahigh-energy cosmic ray interactions as the origin of very high energy $\gamma-$rays from BL Lacs

We explain the observed multiwavelength photon spectrum of a number of BL Lac objects detected at very high energy (VHE, $E \gtrsim 30$ GeV), using a lepto-hadronic emission model. The one-zone leptonic emission is employed to fit the…

High Energy Astrophysical Phenomena · Physics 2021-12-15 Saikat Das , Nayantara Gupta , Soebur Razzaque

A new insight into the innermost jet regions: probing extreme jet variability with LOFT

Blazars are highly variable sources over timescales that can be as low as minutes. This is the case of the High Energy Peaked BL Lac (HBL) objects showing strong variability in X-rays, which highly correlate with that of the TeV emission.…

High Energy Astrophysical Phenomena · Physics 2015-06-17 I. Donnarumma , A. Tramacere , S. Turriziani , L. Costamante , R. Campana , A. De Rosa , E. Bozzo

Variability in the synchrotron self-Compton model of blazar emission

We present a model of the spectra of gamma-ray emitting blazars in which a single homogeneous emission region both emits synchrotron photons directly and scatters them to high (gamma-ray) energy before emission (a ``synchrotron…

Astrophysics · Physics 2016-08-30 A. Mastichiadis , J. G. Kirk

Log-parabolic spectra and particle acceleration in blazars. III: SSC emission in the TeV band from Mkn 501

Curved broad-band spectral distributions of non-thermal sources like blazars are described well by a log-parabolic (LP) law where the second degree term measures the curvature. LP energy spectra can be obtained for relativistic electrons by…

Astrophysics · Physics 2009-11-11 E. Massaro , A. Tramacere , M. Perri , P. Giommi , G. Tosti

Discovery of high and very high-energy emission from the BL Lac object SHBL J001355.9-185406

The detection of the high-frequency peaked BL Lac object (HBL) SHBL J001355.9-185406 ($z$=0.095) at high (HE; 100 MeV$<$E$<$300 GeV) and very high-energy (VHE; $E>100\,{\rm GeV}$) with the \fer\ Large Area Telescope (LAT) and the High…

High Energy Astrophysical Phenomena · Physics 2013-11-19 H. E. S. S. Collaboration , : , A. Abramowski , F. Acero , F. Aharonian , A. G. Akhperjanian , E. Angüner , G. Anton , S. Balenderan , A. Balzer , A. Barnacka , Y. Becherini , J. Becker Tjus , K. Bernlöhr , E. Birsin , E. Bissaldi , J. Biteau , C. Boisson , J. Bolmont , P. Bordas , J. Brucker , F. Brun , P. Brun , T. Bulik , S. Carrigan , S. Casanova , M. Cerruti , P. M. Chadwick , R. Chalme-Calvet , R. C. G. Chaves , A. Cheesebrough , M. Chrétien , 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 , 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 , H. Gast , B. Giebels , J. F. Glicenstein , D. Göring , M. -H. Grondin , M. Grudzińska , S. Häffner , J. D. Hague , 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 , M. Lemoine-Goumard , J. -P. Lenain , D. Lennarz , T. Lohse , A. Lopatin , C. -C. Lu , V. Marandon , A. Marcowith , G. Maurin , N. Maxted , M. Mayer , T. J. L. McComb , M. C. Medina , J. Méhault , U. Menzler , M. Meyer , R. Moderski , M. Mohamed , E. Moulin , T. Murach , C. L. Naumann , M. de Naurois , D. Nedbal , J. Niemiec , S. J. Nolan , L. Oakes , 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 , A. Reimer , O. Reimer , M. Renaud , R. de los Reyes , F. Rieger , L. Rob , 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. Spieß , 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 , M. Vorster , S. J. Wagner , P. Wagner , M. Ward , M. Weidinger , R. White , A. Wierzcholska , P. Willmann , A. Wörnlein , D. Wouters , M. Zacharias , A. Zajczyk , A. A. Zdziarski , A. Zech , H. -S. Zechlin

On the correlation between X-rays and TeV gamma-rays in HBL Blazars

The gamma-ray emission in blazars can be attributed to the leptonic Synchrotron Self-Compton (SSC) model, photo-hadronic interactions, or a combination thereof. While evidence supports both models, their specific contributions remain…

High Energy Astrophysical Phenomena · Physics 2024-12-17 Mabel Osorio-Archila , María Magdalena González , J. Rodrigo Sacahui

VERITAS Observations of Six Bright, Hard-Spectrum Fermi-LAT Blazars

We report on VERITAS very-high-energy (VHE; E>100 GeV) observations of six blazars selected from the Fermi Large Area Telescope First Source Catalog (1FGL). The gamma-ray emission from 1FGL sources was extrapolated up to the VHE band,…

High Energy Astrophysical Phenomena · Physics 2015-06-11 E. Aliu , S. Archambault , T. Arlen , T. Aune , M. Beilicke , W. Benbow , M. Bottcher , A. Bouvier , J. H. Buckley , V. Bugaev , 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 , S. Godambe , S. Griffin , J. Grube , G. Gyuk , D. Hanna , J. Holder , H. Huan , P. Kaaret , N. Karlsson , Y. Khassen , D. Kieda , H. Krawczynski , F. Krennrich , K. Lee , 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 , H. Prokoph , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , E. Roache , D. B. Saxon , G. H. Sembroski , D. Staszak , I. Telezhinsky , G. Tesic , M. Theiling , S. Thibadeau , K. Tsurusaki , A. Varlotta , V. V. Vassiliev , S. Vincent , M. Vivier , S. P. Wakely , T. C. Weekes , A. Weinstein , R. Welsing , D. A. Williams , B. Zitzer , P. Fortin , D. Horan , M. Fumagalli , K. Kaplan , J. X. Prochaska

Intrinsic GeV-TeV gamma-ray emission from EHSP blazars

Extremely High Synchrotron Peak (EHSP) blazars are observed to form a small population of sources with high energy hump peaking at TeV energies in their broad-band spectral energy distributions. The observed gamma-ray emission from these…

High Energy Astrophysical Phenomena · Physics 2019-07-29 K. K. Singh , P. J. Meintjes , N. Bhatt , B. van Soelen

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

We present exactly simultaneous X-ray and TeV monitoring with {\it RXTE} and HEGRA of the TeV blazar Mrk 501 during 15 days in 1998 June. After an initial period of very low flux at both wavelengths, the source underwent a remarkable flare…

Astrophysics · Physics 2009-10-31 Rita M. Sambruna

Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES~2344+514

The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron SED peak energy $\nu_{synch,p}$ above 1keV). While those extreme states were so far observed only during high flux levels, additional…

High Energy Astrophysical Phenomena · Physics 2024-02-14 H. Abe , S. Abe , V. A. Acciari , I. Agudo , T. Aniello , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , C. Arcaro , M. Artero , K. Asano , D. Baack , A. Babić , A. Baquero , U. Barres de Almeida , I. Batković , J. Baxter , J. Becerra González , E. Bernardini , J. Bernete , A. Berti , J. Besenrieder , C. Bigongiari , A. Biland , O. Blanch , G. Bonnoli , Ž Bošjak , I. Burelli , G. Busetto , A. Campoy-Ordaz , A. Carosi , R. Carosi , M. Carretero-Castrillo , A. J. Castro-Tirado , Y. Chai , A. Cifuentes , S. Cikota , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , G. D'Amico , F. D'Ammando , 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 , D. Dominis Prester , D. Dorner , M. Doro , D. Elsaesser , G. Emery , J. Escudero , L. Fariña , A. Fattorini , L. Foffano , L. Font , S. Fukami , Y. Fukazawa , R. J. García López , S. Gasparyan , M. Gaug , J. G. Giesbrecht Paiva , N. Giglietto , F. Giordano , P. Gliwny , R. Grau , J. G. Green , D. Hadasch , A. Hahn , L. Heckmann , J. Herrera , D. Hrupec , M. Hütten , R. Imazawa , T. Inada , R. Iotov , K. Ishio , I. Jiménez Martínez , J. Jormanainen , D. Kerszberg , G. W. Kluge , Y. Kobayashi , P. M. Kouch , H. Kubo , J. Kushida , M. Láinez Lezáun , A. Lamastra , F. Leone , E. Lindfors , L. Linhoff , S. Lombardi , F. Longo , M. López-Moya , A. López-Oramas , S. Loporchio , A. Lorini , B. Machado de Oliveira Fraga , P. Majumdar , M. Makariev , G. Maneva , N. Mang , M. Manganaro , M. Mariotti , M. Martínez , M. Martínez-Chicharro , A. Mas-Aguilar , D. Mazin , S. Menchiari , S. Mender , D. Miceli , T. Miener , J. M. Miranda , R. Mirzoyan , M. Molero González , E. Molina , H. A. Mondal , A. Moralejo , D. Morcuende , T. Nakamori , C. Nanci , V. Neustroev , C. Nigro , L. Nikolić , K. Nishijima , T. Njoh Ekoume , K. Noda , S. Nozaki , Y. Ohtani , A. Okumura , J. Otero-Santos , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , D. Pavlović , M. Persic , M. Pihet , G. Pirola , F. Podobnik , P. G. Prada Moroni , E. Prandini , G. Principe , C. Priyadarshi , W. Rhode , M. Ribó , J. Rico , C. Righi , N. Sahakyan , T. Saito , K. Satalecka , F. G. Saturni , B. Schleicher , K. Schmidt , F. Schmuckermaier , J. L. Schubert , T. Schweizer , A. Sciaccaluga , J. Sitarek , A. Spolon , A. Stamerra , J. Strišović , D. Strom , Y. Suda , H. Tajima , R. Takeishi , F. Tavecchio , P. Temnikov , K. Terauchi , T. Terzić , M. Teshima , L. Tosti , S. Truzzi , A. Tutone , S. Ubach , J. van Scherpenberg , S. Ventura , V. Verguilov , I. Viale , C. F. Vigorito , V. Vitale , R. Walter , C. Wunderlich , T. Yamamoto M. Perri F. Verrecchia C. Leto , S. Das , R. Chatterjee , C. M. Raiteri , M. Villata , E. Semkov , S. Ibryamov , R. Bachev , A. Strigachev , G. Damljanovic , O. Vince , M. D. Jovanovic , M. Stojanovic , V. M. Larionov , T. S. Grishina , E. N. Kopatskaya , E. G. Larionova , D. A. Morozova , S. S. Savchenko , I. S. Troitskiy , Y. V. Troitskaya , A. A. Vasilyev , W. P. Chen , W. J. Hou , C. S. Lin , A. Tsai , S. G. Jorstad , Z. R. Weaver , J. A. Acosta-Pulido , M. I. Carnerero , D. Carosati , S. O. Kurtanidze , O. M. Kurtanidze , B. Jordan , R. Z. Ivanidze , K. Gazeas , K. Vrontaki , T. Hovatta , I. Liodakis , A. C. S. Readhead , S. Kiehlmann , W. Zheng , A. V. Filippenko

Unification of all Blazars

The overall spectra (SED) of blazars, from radio to gamma-ray energies, seem to obey well defined trends, with a continuity of properties between blazars of different classes. To quantify this statement we can either investigate their…

Astrophysics · Physics 2007-05-23 Gabriele Ghisellini

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

Spectral analysis of the blazars Markarian 421 and Markarian 501 with the HAWC Gamma-Ray Observatory

The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high energy sky in the $\sim300$ to 100 TeV energy range and has detected two high-synchrotron-peaked BL Lacertae objects, Markarian 421 and Markarian 501 in a…

High Energy Astrophysical Phenomena · Physics 2019-09-04 Sara Coutiño de León , Alberto Carramiñana Alonso , Daniel Rosa-González , Anna Lia Longinotti

XMM-NuSTAR Observation and Multiwavelength SED Modeling of Blazar 4FGL J1520.8-0348

Active galactic nuclei (AGNs) can power relativistic jets, which are called blazars when pointed close to our line of sight. Depending on the presence or absence of emission lines in their optical spectra, blazars are categorized into flat…

High Energy Astrophysical Phenomena · Physics 2024-04-23 Garima Rajguru , L. Marcotulli , M. Ajello , A. Tramacere

Non-variable TeV emission from the extended jet of a blazar in the stochastic acceleration scenario: the case of the hard TeV emission of 1ES 1101-232

The detections of X-ray emission from the kiloparsec-scale jets of blazars and radio galaxies may imply the existence of high energy electrons in these extended jets, and these electrons could produce high energy emission through inverse…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Dahai Yan , Houdun Zeng , Li Zhang

Discovery of very high energy gamma-ray emission from the BL Lac object PKS 0301-243 with H.E.S.S

The active galactic nucleus PKS 0301-243 (z=0.266) is a high-synchrotron-peaked BL Lac object that is detected at high energies (HE, 100 MeV < E < 100 GeV) by Fermi/LAT. This paper reports on the discovery of PKS 0301-243 at very high…

High Energy Astrophysical Phenomena · Physics 2015-06-17 H. E. S. S. Collaboration , A. Abramowski , F. Acero , F. Aharonian , F. Ait , A. G. Akhperjanian , E. Angüner , G. Anton , S. Balenderan , A. Balzer , A. Barnacka , Y. Becherini , J. Becker , 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 , M. Cerruti , P. M. Chadwick , R. Chalme-Calvet , R. C. G. Chaves , A. Cheesebrough , M. Chrétien , 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 , 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 , B. Giebels , J. F. Glicenstein , M. -H. Grondin , M. Grudzìnska , S. Häffner , J. D. Hague , 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 , M. Lemoine-Goumard , J. -P. Lenain , D. Lennarz , T. Lohse , A. Lopatin , C. -C. Lu , V. Marandon , A. Marcowith , R. Marx , G. Maurin , N. Maxted , M. Mayer , T. J. L. McComb , M. C. Medina , J. Méhault , U. Menzler , M. Meyer , R. Moderski , M. Mohamed , E. Moulin , T. Murach , C. L. Naumann , M. de Naurois , D. Nedbal , J. Niemiec , S. J. Nolan , L. Oakes , 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 , A. Reimer , O. Reimer , M. Renaud , R. de los Reyes , F. Rieger , L. Rob , 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 , L. 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 , M. Vorster , S. J. Wagner , P. Wagner , M. Ward , M. Weidinger , Q. Weitzel , R. White , A. Wierzcholska , P. Willmann , A. Wörnlein , D. Wouters , M. Zacharias , A. Zajczyk , A. A. Zdziarski , A. Zech , H. -S. Zechlin

Studies of Extragalactic Background Light with TeV BL Lac Objects

Very high energy (VHE; $E \geq$ 100GeV) $\gamma-$ray from cosmological distances are attenuated by the extragalactic background light (EBL) in the IR to UV band. By contrasting measured versus intrinsic emission, the EBL photon density can…

High Energy Astrophysical Phenomena · Physics 2020-09-01 Longhua Qin , Jiancheng Wang , Quangui Gao , Weiwei Na , Huaizhen Li , Ju Ma , Jianping Yang

Identification of extragalactic sources of the highest energy EGRET photons by correlation analysis

We found significant correlations between the arrival directions of the highest energy photons (E>10 GeV) observed by EGRET and positions of the BL Lac type objects (BL Lacs). The observed correlations imply that not less than three per…

Astrophysics · Physics 2008-11-26 D. S. Gorbunov , P. G. Tinyakov , I. I. Tkachev , S. V. Troitsky