Related papers: The TeV blazar Markarian 421 at the highest spatia…

Multi-wavelength observations of the TeV Blazars Mkn~421, 1ES1959+650, and H1426+428 with the HEGRA Cherenkov telescopes and the RXTE X-ray satellite

Recent results obtained with the HEGRA system of imaging Cherenkov telescopes on the TeV emission of the Blazars Mkn~421 ($z=0.030$), 1ES1959+650 ($z=0.047$), and H1426+428 ($z=0.129$) are reported. For Mkn~421, a close connection of the…

Astrophysics · Physics 2007-05-23 D. Horns , the HEGRA collaboration

Multiwavelength Observations of the Blazar VER J0521+211 During an Elevated TeV Gamma-Ray State

We report on a long-lasting, elevated gamma-ray flux state from VER J0521+211 observed by VERITAS, MAGIC, and Fermi-LAT in 2013 and 2014. The peak integral flux above 200 GeV measured with the nightly-binned light curve is $(8.8 \pm 0.4)…

High Energy Astrophysical Phenomena · Physics 2022-08-10 The VERITAS Collaboration , The MAGIC Collaboration

SST-1M Observations of Markarian 421

Markarian 421 (Mrk 421) is the closest and one of the brightest high-frequency peaked blazars, located at a redshift of z = 0.031. It is a strong source of gamma rays, and its broadband emission has been extensively studied over the years…

High Energy Astrophysical Phenomena · Physics 2025-07-25 Srija Reddy Muthyala , Anabella Araudo , Jakub Juryšek , Ana Laura Müller

Five-year Monitorings of TeV Blazars with ASCA and RXTE

We study the temporal/spectral variability of two extragalactic TeV sources, Mrk 421 and Mrk 501, based on 5-year observations with the ASCA and RXTE satellites. We found that the peak of the synchrotron emission exists just in the X-ray…

Astrophysics · Physics 2007-05-23 J. Kataoka , T. Takahashi , F. Takahara , P. G. Edwards , K. Hayashida , S. Inoue , N. Iyomoto , N. Kawai , G. M. Madejski , C. Tanihata , S. J. Wagner

Long-term multi-band photometric monitoring of Mrk 501

Radio-to-TeV observations of the bright nearby (z=0.034) blazar Markarian 501 (Mrk 501), performed from December 2012 to April 2018, are used to study the emission mechanisms in its relativistic jet. We examined the multi-wavelength…

High Energy Astrophysical Phenomena · Physics 2021-12-01 Axel Arbet-Engels , Dominik Baack , Matteo Balbo , Adrian Biland , Thomas Bretz , Jens Buss , Daniela Dorner , Laura Eisenberger , Dominik Elsaesser , Dorothee Hildebrand , Roman Iotov , Adelina Kalenski , Karl Mannheim , Alison Mitchell , Dominik Neise , Maximilian Noethe , Aleksander Paravac , Wolfgang Rhode , Bernd Schleicher , Vitalii Sliusar , Roland Walter

Long-term spectra of the blazars Mrk 421 and Mrk 501 at TeV energies seen by HAWC

The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high energy sky in the 300 GeV to $>100$ TeV energy range. HAWC has detected two blazars above $11\sigma$, Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501).…

High Energy Astrophysical Phenomena · Physics 2022-04-27 A. Albert , R. Alfaro , C. Alvarez , J. R. Angeles Camacho , J. C. Arteaga-Velázquez , K. P. Arunbabu , D. Avila Rojas , H. A. Ayala Solares , V. Baghmanyan , Belmont-Moreno , K. S. Caballero-Mora , T. Capistrán , A. Carramiñana , S. Casanova , U. Cotti , J. Cotzomi , S. Coutiño de León , E. De la Fuente , R. Diaz Hernandez , M. A. DuVernois , M. Durocher , J. C. Díaz-Vélez , K. Engel , C. Espinoza , K. L. Fan , M. Fernández Alonso , N. Fraija , D. Garcia , J. A. García-González , F. Garfias , M. M. González , J. A. Goodman , J. P. Harding , B. Hona , D. Huang , F. Hueyotl-Zahuantitla , P. Hüntemeyer , A. Iriarte , V. Joshi , A. Lara , W. H. Lee , J. Lee , H. León Vargas , A. L. Longinotti , G. Luis-Raya , K. Malone , O. Martinez , J. Martínez-Castro , J. A. Matthews , P. Miranda-Romagnoli , E. Moreno , M. Mostafá , A. Nayerhoda , L. Nellen , M. Newbold , R. Noriega-Papaqui , A. Peisker , Y. Pérez Araujo , E. G. Pérez-Pérez , C. D. Rho , D. Rosa-González , H. Salazar , F. Salesa Greus , A. Sandoval , M. Schneider , J. Serna-Franco , A. J. Smith , R. W. Springer , K. Tollefson , I. Torres , R. Torres-Escobedo , F. Ureña-Mena , L. Villaseñor , X. Wang , T. Weisgarber , E. Willox , H. Zhou , C. de León

Very High Energy Gamma-Ray Emission from the Blazar Markarian 421

Very high energy gamma-ray emission from the BL Lac object Markarian 421 has been detected over three observing seasons on 59 nights between April 1992 and June 1994 with the Whipple 10-meter imaging Cherenkov telescope. During its initial…

Astrophysics · Physics 2009-10-28 M. S. Schubnell , C. W. Akerlof , S. Biller J. Buckley , D. A. Carter-Lewis , M. F. Cawley , M. Chantell , V. Connaughton , D. J. Fegan , S. Fennell , J. A. Gaidos , A. M. Hillas , A. D. Kerrick R. C. Lamb , D. I. Meyer , G. Mohanty , J. Rose , A. C. Rovero , G. Sembroski , T. C. Weekes , C. Wilson , J. Zweerink

Extreme HBL-like behavior of Markarian 421 and its two-zone photohadronic interpretation

Markarian 421 is the nearest high-energy peaked blazar and also is the first extragalactic source to be detected in multi-TeV $\gamma$-rays. It has been observed in multiwavelength for exceptionally long period of time with dense monitoring…

High Energy Astrophysical Phenomena · Physics 2021-06-30 Sarira Sahu , Carlos E. López Fortín , Isabel Abigail Valadez Polanco , Subhash Rajpoot

Gamma ray flares from Mrk421 in 2008 observed with the ARGO-YBJ detector

In 2008 the blazar Markarian 421 entered a very active phase and was one of the brightest sources in the sky at TeV energies, showing frequent flaring episodes. Using the data of ARGO-YBJ, a full coverage air shower detector located at…

High Energy Astrophysical Phenomena · Physics 2015-05-18 G. Aielli et al.

The June 2008 flare of Markarian 421 from optical to TeV energies

We present optical to very-high energy (VHE) gamma-ray observations of Mrk 421 between 2008 May 24 and June 23. A high-energy (HE) gamma-ray signal was detected by AGILE-GRID during June 9-15, brighter than the average flux observed by…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-15 R. M. Wagner , I. Donnarumma , J. Grube , M. Villata , C. M. Raiteri , C. -C. Hsu , K. Satalecka , E. Bernardini , P. Majumdar

Characterization of Markarian 421 during its most violent year: Multiwavelength variability and correlations

Mrk 421 was in its most active state around early 2010, which led to the highest TeV gamma-ray flux ever recorded from any active galactic nuclei. We aim to characterize the multiwavelength behavior during this exceptional year for Mrk 421,…

High Energy Astrophysical Phenomena · Physics 2025-01-08 K. Abe , S. Abe , J. Abhir , A. Abhishek , V. A. Acciari , A. Aguasca-Cabot , I. Agudo , T. Aniello , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , C. Arcaro , K. Asano , D. Baack , A. Babić , U. Barres de Almeida , J. A. Barrio , I. Batković , A. Bautista , J. Baxter , J. Becerra González , W. Bednarek , E. Bernardini , J. Bernete , A. Berti , J. Besenrieder , C. Bigongiari , A. Biland , O. Blanch , G. Bonnoli , Ž. Bošnjak , E. Bronzini , I. Burelli , A. Campoy-Ordaz , R. Carosi , M. Carretero-Castrillo , A. J. Castro-Tirado , D. Cerasole , G. Ceribella , Y. Chai , A. Cifuentes , 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 , R. de Menezes , M. Delfino , J. Delgado , C. Delgado Mendez , F. Di Pierro , R. Di Tria , L. Di Venere , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , L. Eisenberger , D. Elsaesser , J. Escudero , L. Fariña , A. Fattorini , L. Foffano , L. Font , S. Fröse , S. Fukami , Y. Fukazawa , R. J. García López , M. Garczarczyk , S. Gasparyan , M. Gaug , J. G. Giesbrecht Paiva , N. Giglietto , F. Giordano , P. Gliwny , N. Godinović , T. Gradetzke , R. Grau , D. Green , J. G. Green , P. Günther , D. Hadasch , A. Hahn , T. Hassan , L. Heckmann , J. Herrera Llorente , D. Hrupec , R. Imazawa , K. Ishio , I. Jiménez Martínez , J. Jormanainen , S. Kankkunen , T. Kayanoki , D. Kerszberg , G. W. Kluge , P. M. Kouch , H. Kubo , J. Kushida , M. Láinez , A. Lamastra , F. Leone , E. Lindfors , S. Lombardi , F. Longo , R. López-Coto , M. López-Moya , A. López-Oramas , S. Loporchio , A. Lorini , P. Majumdar , M. Makariev , G. Maneva , M. Manganaro , S. Mangano , K. Mannheim , 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 , L. Nickel , C. Nigro , L. Nikolić , K. Nilsson , K. Nishijima , T. Njoh Ekoume , K. Noda , S. Nozaki , A. Okumura , J. Otero-Santos , S. Paiano , D. Paneque , R. Paoletti , J. M. Paredes , M. Peresano , M. Persic , M. Pihet , G. Pirola , F. Podobnik , P. G. Prada Moroni , E. Prandini , G. Principe , W. Rhode , M. Ribó , J. Rico , C. Righi , N. Sahakyan , T. Saito , F. G. Saturni , K. Schmidt , F. Schmuckermaier , J. L. Schubert , T. Schweizer , A. Sciaccaluga , G. Silvestri , J. Sitarek , D. Sobczynska , A. Stamerra , J. Strišković , D. Strom , Y. Suda , H. Tajima , M. Takahashi , R. Takeishi , F. Tavecchio , P. Temnikov , K. Terauchi , T. Terzić , M. Teshima , S. Truzzi , A. Tutone , S. Ubach , J. van Scherpenberg , S. Ventura , G. Verna , I. Viale , C. F. Vigorito , V. Vitale , I. Vovk , R. Walter , F. Wersig , M. Will , T. Yamamoto , S. G. Jorstad , A. P. Marscher , M. Perri , C. Leto , F. Verrecchia , M. Aller , W. Max-Moerbeck , A. C. S. Readhead , A. Lähteenmäki , M. Tornikoski , M. A. Gurwell , A. E. Wehrle

ANTARES search for high-energy neutrinos from TeV-emitting blazars, Markarian 421 and 501, in coincidence with HAWC gamma-ray flares

An updated analysis of a targeted search for high-energy neutrinos from Markarian 421 and Markarian 501 is reported. They are two of the closest and brightest extragalactic sources in the TeV band. In contrast to other types of active…

High Energy Astrophysical Phenomena · Physics 2019-11-13 Mukharbek Organokov , Thierry Pradier

Estimating the redshift of PKS 0447-439 through its GeV-TeV emission

Context. Blazars are radio-loud active galactic nuclei (AGN) with a jet pointing at small angles towards the observer. The overall emitted spectrum is typically non-thermal, and in some cases the emission and/or absorption lines are so…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-06 Elisa Prandini , Giacomo Bonnoli , Fabrizio Tavecchio

A search for spectral hysteresis and energy-dependent time lags from X-ray and TeV gamma-ray observations of Mrk 421

Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars simultaneously at different wavelengths, especially in the X-ray and gamma-ray…

High Energy Astrophysical Phenomena · Physics 2016-12-28 A. U. Abeysekara , S. Archambault , A. Archer , W. Benbow , R. Bird , M. Buchovecky , J. H. Buckley , V. Bugaev , J. V Cardenzana , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , J. D. Eisch , A. Falcone , Q. Feng , J. P. Finley , H. Fleischhack , A. Flinders , L. Fortson , A. Furniss , S. Griffin , M. Hütten , N. Håkansson , D. Hanna , O. Hervet , J. Holder , T. B. Humensky , P. Kaaret , P. Kar , M. Kertzman , D. Kieda , M. Krause , S. Kumar , M. J. Lang , G. Maier , S. McArthur , A. McCann , K. Meagher , P. Moriarty , R. Mukherjee , D. Nieto , S. O'Brien , R. A. Ong , A. N. Otte , N. Park , V. Pelassa , M. Pohl , A. Popkow , E. Pueschel , K. Ragan , P. T. Reynolds , G. T. Richards , E. Roache , I. Sadeh , M. Santander , G. H. Sembroski , K. Shahinyan , D. Staszak , I. Telezhinsky , J. V. Tucci , J. Tyler , S. P. Wakely , A. Weinstein , A. Wilhelm , D. A. Williams , M. L. Ahnen , S. Ansoldi , L. A. Antonelli , P. Antoranz , C. Arcaro , A. Babic , B. Banerjee , P. Bangale , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , E. Bernardini , A. Berti , B. Biasuzzi , A. Biland , O. Blanch , S. Bonnefoy , G. Bonnoli , F. Borracci , T. Bretz , R. Carosi , A. Carosi , A. Chatterjee , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Cumani , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , E. de Oña Wilhelmi , F. Di Pierro , M. Doert , A. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Eisenacher Glawion , D. Elsaesser , M. Engelkemeier , V. Fallah Ramazani , A. Fernández-Barral , D. Fidalgo , M. V. Fonseca , L. Font , C. Fruck , D. Galindo , R. J. García López , M. Garczarczyk , M. Gaug , P. Giammaria , N. Godinović , D. Gora , D. Guberman , D. Hadasch , A. Hahn , T. Hassan , M. Hayashida , J. Herrera , J. Hose , D. Hrupec , G. Hughes , W. Idec , K. Kodani , Y. Konno , H. Kubo , J. Kushida , D. Lelas , E. Lindfors , S. Lombardi , F. Longo , M. López , R. López-Coto , P. Majumdar , M. Makariev , K. Mallot , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , B. Marcote , M. Mariotti , M. Martínez , D. Mazin , U. Menzel , R. Mirzoyan , A. Moralejo , E. Moretti , D. Nakajima , V. Neustroev , A. Niedzwiecki , M. Nievas Rosillo , K. Nilsson , K. Nishijima , K. Noda , L. Nogués , M. Nöthe , S. Paiano , J. Palacio , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , X. Paredes-Fortuny , G. Pedaletti , M. Peresano , L. Perri , M. Persic , J. Poutanen , P. G. Prada Moroni , E. Prandini , I. Puljak , J. R. Garcia , I. Reichardt , W. Rhode , M. Ribó , J. Rico , T. Saito , K. Satalecka , S. Schroeder , T. Schweizer , S. N. Shore , A. Sillanpää , J. Sitarek , I. Snidaric , D. Sobczynska , A. Stamerra , M. Strzys , T. Surić , L. Takalo , F. Tavecchio , P. Temnikov , T. Terzić , D. Tescaro , M. Teshima , D. F. Torres , N. Torres-Albà , T. Toyama , A. Treves , G. Vanzo , M. Vazquez Acosta , I. Vovk , J. E. Ward , M. Will , M. H. Wu , R. Zanin , T. Hovatta , I. de la Calle Perez , P. S. Smith , E. Racero , M. Baloković

Very Long Baseline polarimetry and the gamma-ray connection in Markarian 421 during the broadband campaign in 2011

We analyzed data in polarized intensity obtained with the Very Long Baseline Array (VLBA) at twelve epochs (one observation per month from January to December 2011) at 15, 24, and 43 GHz. For the absolute orientation of the electric vector…

High Energy Astrophysical Phenomena · Physics 2014-11-11 R. Lico , M. Giroletti , M. Orienti , G. Giovannini , J. L. Gomez , C. Casadio , F. D'Ammando , M. G. Blasi , W. Cotton , P. G. Edwards , L. Fuhrmann , S. Jorstad , M. Kino , Y. Y. Kovalev , T. P. Krichbaum , A. P. Marscher , D. Paneque , G. Piner , K. Sokolovsky

Temporal and spectral gamma-ray properties of Mkn421 above 250 GeV from CAT observations between 1996 and 2000

The gamma-ray emission above 250 GeV from the BL Lac object Markarian 421 was observed by the CAT Cherenkov imaging telescope between December, 1996, and June, 2000. In 1998, the source produced a series of small flares, making it the…

Astrophysics · Physics 2014-10-13 F. Piron , A. Djannati-Atai , M. Punch , J. -P. Tavernet , A. Barrau , R. Bazer-Bachi , L. -M. Chounet , G. Debiais , B. Degrange , J. -P. Dezalay , P. Espigat , B. Fabre , P. Fleury , G. Fontaine , P. Goret , C. Gouiffes , B. Khelifi , I. Malet , C. Masterson , G. Mohanty , E. Nuss , C. Renault , M. Rivoal , L. Rob , S. Vorobiov

A time dependent approach to model X-ray and $\gamma$--ray light curves of Mrk 421 observed during the flare in February 2010

Strong X-ray and $\gamma$--ray flares have been detected in February 2010 from the high synchrotron peaked blazar Mrk 421 (z=0.031). With the motivation of understanding the physics involved in this flaring activity, we study the…

High Energy Astrophysical Phenomena · Physics 2017-01-11 K K Singh , S Sahayanathan , A Sinha , N Bhatt , A K Tickoo , K K Yadav , R C Rannot , P Chandra , K Venugopal , P Marandi , N Kumar , H C Goyal , A Goyal , N K Agarwal , M Kothari , K Chanchalani , V K Dhar , N Chouhan , C K Bhat , M K Koul , R Koul

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

Long-term optical polarization variability of the tev blazar 1es~1959+650

A detailed analysis of the optical polarimetric variability of the TeV blazar 1ES 1959+650 from 2007 October 18 to 2011 May 5 is presented. The source showed a maximum and minimum brightness states in the R-band of 14.08$\pm$0.03 mag and…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Marco Sorcia , Erika Benítez , David Hiriart , José M. López , José I. Cabrera , Raúl Mújica , Jochen Heidt , Ivan Agudo , Kari Nilsson , Michael Mommert

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