Related papers: Hourly Spectral Variability of Mrk 421

Time-Dependent Modeling of the Sub-Hour Spectral Evolution During the 2013 Outburst of Mrk 421

In April 2013, the TeV blazar Markarian~421 underwent one of its most powerful emission outbursts to date. An extensive multi-instrument campaign featuring MAGIC, VERITAS, and \textit{NuSTAR} provided comprehensive very-high-energy (VHE; $E…

High Energy Astrophysical Phenomena · Physics 2026-03-06 MAGIC Collaboration , K. Abe , S. Abe , J. Abhir , A. Abhishek , A. Aguasca-Cabot , I. Agudo , T. Aniello , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , C. Arcaro , T. T. H. Arnesen , A. Babić , C. Bakshi , U. Barres de Almeida , J. A. Barrio , L. Barrios-Jiménez , I. Batković , J. Baxter , J. Becerra González , W. Bednarek , E. Bernardini , J. Bernete , A. Berti , C. Bigongiari , A. Biland , O. Blanch , G. Bonnoli , Ž Bošnjak , E. Bronzini , I. Burelli , A. Campoy-Ordaz , A. Carosi , R. Carosi , M. Carretero-Castrillo , A. J. Castro-Tirado , D. Cerasole , G. Ceribella , Y. Chai , A. Cifuentes , J. L. Contreras , J. Cortina , S. Covino , F. D'Ammando , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , R. de Menezes , J. Delgado , C. Delgado Mendez , F. Di Pierro , R. Di Tria , L. Di Venere , A. Dinesh , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , L. Eisenberger , D. Elsaesser , J. Escudero , L. Fariña , L. Foffano , L. Font , S. Fröse , Y. Fukazawa , R. J. García López , S. García Soto , M. Garczarczyk , S. Gasparyan , J. G. Giesbrecht Paiva , N. Giglietto , F. Giordano , P. Gliwny , T. Gradetzke , R. Grau , D. Green , J. G. Green , P. Günther , A. Hahn , T. Hassan , L. Heckmann , J. Herrera Llorente , D. Hrupec , D. Israyelyan , J. Jahanvi , I. Jiménez Martínez , J. Jiménez Quiles , J. Jormanainen , S. Kankkunen , T. Kayanoki , J. Konrad , P. M. Kouch , G. Koziol , H. Kubo , J. Kushida , M. Laínez , A. Lamastra , E. Lindfors , S. Lombardi , F. Longo , M. López-Moya , A. López-Oramas , S. Loporchio , L. Lulić , E. Lyard , P. Majumdar , M. Makariev , M. Mallamaci , G. Maneva , M. Manganaro , S. Mangano , K. Mannheim , S. Marchesi , M. Mariotti , M. Martínez , P. Maruševec , S. Menchiari , J. Méndez Gallego , S. Menon , D. Miceli , J. M. Miranda , R. Mirzoyan , M. Molero González , E. Molina , H. A. Mondal , A. Moralejo , C. Nanci , A. Negro , V. Neustroev , L. Nickel , M. Nievas Rosillo , C. Nigro , L. Nikolić , 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 , W. Rhode , M. Ribó , J. Rico , A. Roy , N. Sahakyan , F. G. Saturni , K. Schmitz , F. Schmuckermaier , T. Schweizer , A. Sciaccaluga , G. Silvestri , A. Simongini , J. Sitarek , V. Sliusar , D. Sobczynska , A. Stamerra , J. Strišković , D. Strom , M. Strzys , Y. Suda , H. Tajima , R. Takeishi , F. Tavecchio , T. Terzić , M. Teshima , A. Tutone , S. Ubach , J. van Scherpenberg , M. Vazquez Acosta , S. Ventura , G. Verna , I. Viale , A. Vigliano , C. F. Vigorito , E. Visentin , V. Vitale , I. Vovk , R. Walter , F. Wersig , M. Will , T. Yamamoto , P. K. H. Yeung , M. Petropoulou , M. Polkas , A. Mastichiadis

Short-Timescale Variability of the Blazar Mrk 421 from AstroSat and Simultaneous Multi-Wavelength Observations

We study the multi-wavelength variability of the blazar Mrk 421 at minutes to days timescales using simultaneous data at $\gamma$-rays from Fermi, 0.7-20 keV energies from AstroSat, and optical and near-infrared (NIR) wavelengths from…

High Energy Astrophysical Phenomena · Physics 2023-07-20 Ritaban Chatterjee , Susmita Das , Archishman Khasnovis , Ritesh Ghosh , Neeraj Kumari , Sachindra Naik , V. M. Larionov , T. S. Grishina , E. N. Kopatskaya , E. G. Larionova , A. A. Nikiforova , D. A. Morozov , S. S. Savchenko , Yu. V. Troitskaya , I. S. Troitsky , A. A. Vasilyev

The 2014 TeV Gamma-ray Flare of Mrk 501 Seen with H.E.S.S.: Temporal and Spectral Constraints on Lorentz Invariance Violation

The blazar Mrk 501 (z=0.034) was observed at very-high-energy (VHE, $E\gtrsim 100$~GeV) gamma-ray wavelengths during a bright flare on the night of 2014 June 23-24 (MJD 56832) with the H.E.S.S. phase-II array of Cherenkov telescopes. Data…

High Energy Astrophysical Phenomena · Physics 2019-01-17 H. E. S. S. Collaboration , : , H. Abdalla , F. Aharonian , F. Ait Benkhali , E. O. Angüner , M. Arakawa , C. Arcaro , C. Armand , M. Arrieta , M. Backes , M. Barnard , Y. Becherini , J. Becker Tjus , D. Berge , S. Bernhard , K. Bernlöhr , R. Blackwell , M. Böttcher , C. Boisson , J. Bolmont , S. Bonnefoy , P. Bordas , J. Bregeon , F. Brun , P. Brun , M. Bryan , M. Büchele , T. Bulik , T. Bylund , M. Capasso , S. Caroff , A. Carosi , S. Casanova , M. Cerruti , N. Chakraborty , S. Chandra , R. C. G. Chaves , A. Chen , S. Colafrancesco , B. Condon , I. D. Davids , C. Deil , J. Devin , P. deWilt , L. Dirson , A. Djannati-Ataï , A. Dmytriiev , A. Donath , L. O'C. Drury , J. Dyks , K. Egberts , G. Emery , J. -P. Ernenwein , S. Eschbach , S. Fegan , A. Fiasson , G. Fontaine , S. Funk , M. Füßling , S. Gabici , Y. A. Gallant , T. Garrigoux , 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 , A. Jacholkowska , M. Jamrozy , D. Jankowsky , F. Jankowsky , L. Jouvin , I. Jung-Richardt , M. A. Kastendieck , K. Katarzyński , M. Katsuragawa , U. Katz , D. Kerszberg , D. Khangulyan , B. Khélifi , J. King , S. Klepser , W. Kluźniak , Nu. Komin , K. Kosack , S. Krakau , M. Kraus , P. P. Krüger , G. Lamanna , J. Lau , J. Lefaucheur , A. Lemière , M. Lemoine-Goumard , J. -P. Lenain , E. Leser , T. Lohse , M. Lorentz , R. López-Coto , I. Lypova , D. Malyshev , V. Marandon , A. Marcowith , C. Mariaud , G. Guillem Martí-Devesa , R. Marx , G. Maurin , P. J. Meintjes , A. M. W. Mitchell , R. Moderski , M. Mohamed , L. Mohrmann , E. Moulin , T. Murach , S. Nakashima , M. de Naurois , H. Ndiyavala , F. Niederwanger , J. Niemiec , L. Oakes , P. O'Brien , H. Odaka , S. Ohm , M. Ostrowski , I. Oya , M. Padovani , 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 , 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 , U. Schwanke , S. Schwemmer , M. Seglar-Arroyo , M. Senniappan , A. S. Seyffert , N. Shafi , I. Shilon , K. Shiningayamwe , R. Simoni , A. Sinha , H. Sol , F. Spanier , A. Specovius , M. Spir-Jacob , Ł. Stawarz , R. Steenkamp , C. Stegmann , C. Steppa , I. Sushch , T. Takahashi , J. -P. Tavernet , T. Tavernier , A. M. Taylor , R. Terrier , L. Tibaldo , 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 , A. Viana , P. Vincent , J. Vink , F. Voisin , H. J. Völk , T. Vuillaume , Z. Wadiasingh , S. J. Wagner , P. Wagner , R. M. Wagner , R. White , A. Wierzcholska , A. Wörnlein , R. Yang , D. Zaborov , M. Zacharias , R. Zanin , A. A. Zdziarski , A. Zech , F. Zefi , A. Ziegler , J. Zorn , N. Żywucka

4.5-year simultaneous multi-wavelength observation of Mrk 421 in the ARGO-YBJ and Fermi overlap era

As one of the most active blazars, Mrk421 is an excellent candidate for the study of the physical processes within the jets of AGN. Here we report on the extensive multi-wavelength observations of Mrk 421 over 4.5 years, from 2008 August to…

High Energy Astrophysical Phenomena · Physics 2015-10-08 Songzhan Chen , Silvia Vernetto

Multiwavelength observations of the blazar BL Lacertae: a new fast TeV $\gamma$-ray flare

Observations of fast TeV $\gamma$-ray flares from blazars reveal the extreme compactness of emitting regions in blazar jets. Combined with very-long-baseline radio interferometry measurements, they probe the structure and emission mechanism…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Q. Feng , S. G. Jorstad , A. P. Marscher , M. L. Lister , Y. Y. Kovalev , A. B. Pushkarev , T. Savolainen , I. Agudo , S. N. Molina , J. L. Gomez , V. M. Larionov , G. A. Borman , A. A. Mokrushina , P. S. Smith

The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65

Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole…

High Energy Astrophysical Phenomena · Physics 2021-05-12 C. M. Raiteri , M. Villata , V. M. Larionov , S. G. Jorstad , A. P. Marscher , Z. R. Weaver

Systematic investigation of X-ray spectral variability of TeV blazars during flares in the $RXTE$ era

Utilizing all the 16-year $RXTE$ observations, we analyze the X-ray spectra of 32 TeV blazars, and perform a systematic investigation of X-ray spectral variability for the 5 brightest sources during their major flares that lasted several…

Astrophysics of Galaxies · Physics 2018-11-07 Yijun Wang , Yongquan Xue , Shifu Zhu , Junhui Fan

Optical Flux and Spectral Variability of the TeV blazar PG 1553+113

We present the results of our optical (VRI) observations of the TeV blazar PG 1553+113 over eight nights in 2016 April. We monitored the blazar quasi-simultaneously in V and R bands each night and examined the light curves (LCs) for…

High Energy Astrophysical Phenomena · Physics 2019-03-29 Ashwani Pandey , Alok C. Gupta , Paul J. Wiita , S. N. Tiwari

X-ray Spectral Variability of TeV Blazars during Rapid Flares

The spectral energy distribution (SED) of TeV blazars peaks both at keV and TeV energies. The X-ray emission is generally believed to originate in the synchrotron emission from relativistic electrons (and positrons) in the jet of these…

Astrophysics · Physics 2008-11-26 Yongquan Xue , Feng Yuan , Wei Cui

Multiwavelength study of TeV Blazar Mrk421 during giant flare and observations of TeV AGNs with HAGAR

The radiation mechanism of very high energy $\gamma$-ray emission from blazars and crucial parameters like magnetic field, and size of the emitting region are not well understood yet. To understand the above mentioned properties of blazars,…

High Energy Astrophysical Phenomena · Physics 2011-11-01 A. Shukla , P. R. Vishwanath , G. C. Anupama , T. P. Prabhu , V. R. Chitnis , B. S. Acharya , R. J. Britto , B. B. Singh , P. Bhattacharjee , L. Saha

INTEGRAL and Multiwavelength Observations of the Blazar Mrk 421 during an Active Phase

A ToO observation of the TeV-emitting blazar Mrk 421 with INTEGRAL was triggered in June 2006 by an increase of the RXTE count rate to more than 30 mCrab. The source was then observed with all INTEGRAL instruments with the exception of the…

Astrophysics · Physics 2009-06-23 G. G. Lichti , E. Bottacini , P. Charlot , W. Collmar , D. Horan , A. von Kienlin , A. Laehteenmaeki , K. Nilsson , D. Petry , A. Sillanpaeae , M. Tornikoski , T. Weekes

Characteristic X-ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine

We have studied the rapid X-ray variability of three extragalactic TeV gamma-ray sources; Mrk 421, Mrk 501 and PKS 2155-304. Analyzing the X-ray light curves obtained from ASCA and/or RXTE observations between 1993 and 1998, we have…

Astrophysics · Physics 2009-11-06 Jun Kataoka , Tadayuki Takahashi , Stefan J. Wagner , Naoko Iyomoto , Philip G. Edwards , Kiyoshi Hayashida , Susumu Inoue , Greg M. Madejski , Fumio Takahara , Chiharu Tanihata , Nobuyuki Kawai

The Energy Spectrum of the Blazar Markarian 421 Above 130 GeV

Markarian 421 (Mrk 421) was the first blazar detected at gamma-ray energies above 300 GeV, and it remains one of only twelve TeV blazars detected to date. TeV gamma-ray measurements of its flaring activity and spectral variability have…

Astrophysics · Physics 2008-11-26 J. E. Carson , J. Kildea , R. A. Ong , J. Ball , D. A. Bramel , C. E. Covault , D. Driscoll , P. Fortin , D. M. Gingrich , D. S. Hanna , T. Lindner , C. Mueller , A. Jarvis , R. Mukherjee , K. Ragan , R. A. Scalzo , D. A. Williams , J. Zweerink

Multifrequency Variability and Correlations from Extensive Observing Campaigns of Mkn 421 and Mkn 501 in 2009

We are performing an unprecedentedly long and dense monitoring of the multi-frequency (radio to TeV) emission from the classical TeV blazars Mkn 421 and Mkn 501. These objects are among the brightest X-ray/TeV blazars in the sky and among…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Ulisses Barres de Almeida , David Paneque , Nina Nowak , Nikola Strah , Diego Tescaro

Near Infrared Intraday Variability of Mrk 421

We report results from our monitoring of the BL Lac object Mrk 421 in the near-IR $J$ band. The observations, aimed at studying the intraday variability (IDV) of the object, were carried out systematically over an extended (and…

Astrophysics · Physics 2009-11-10 A. C. Gupta , D. P. K. Banerjee , N. M. Ashok , U. C. Joshi

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

BeppoSAX Observations of the TeV Blazar Mkn 421

The blazar Mkn 421 has been observed, as part of the AO1 Core Program, five times from 2 to 7 May 1997. In the LECS+MECS energy band the spectrum shows convex curvature, well represented by a broken power--law. Flux variability (more than a…

Astrophysics · Physics 2019-08-15 G. Fossati , L. Chiappetti

Time-dependent modelling of short-term variability in the TeV-blazar VER J0521+211 during the major flare in 2020

The BL Lacertae object VER J0521+211 underwent a notable flaring episode in February 2020. A short-term monitoring campaign, led by the MAGIC (Major Atmospheric Gamma Imaging Cherenkov) collaboration, covering a wide energy range from radio…

High Energy Astrophysical Phenomena · Physics 2025-02-26 MAGIC Collaboration , 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 , M. Artero , 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 , A. Carosi , 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 , 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 , 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 , Y. Kobayashi , 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 , E. Lyard , B. Machado de Oliveira Fraga , 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 , M. Nievas Rosillo , C. Nigro , L. Nikolić , K. Nilsson , K. Nishijima , T. Njoh Ekoume , K. Noda , S. Nozaki , Y. Ohtani , 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 , V. Sliusar , D. Sobczynska , A. Spolon , A. Stamerra , J. Strišković , D. Strom , M. Strzys , Y. Suda , H. Tajima , M. Takahashi , R. Takeishi , P. Temnikov , K. Terauchi , T. Terzić , M. Teshima , S. Truzzi , A. Tutone , S. Ubach , J. van Scherpenberg , M. Vazquez Acosta , S. Ventura , G. Verna , I. Viale , C. F. Vigorito , V. Vitale , I. Vovk , R. Walter , F. Wersig , M. Will , C. Wunderlich , T. Yamamoto , MWL collaborators , : , R. Bachev , V. Fallah Ramazani , A. V. Filippenko , T. Hovatta , S. G. Jorstad , S. Kiehlmann , A. Lähteenmäki , I. Liodakis , A. P. Marscher , W. Max-Moerbeck , A. Omeliukh , T. Pursimo , A. C. S. Readhead , X. Rodrigues , M. Tornikoski , F. Wierda , W. Zheng

Multi-color Optical Variability of the TeV Blazar Mrk 501 in the Low-State

We report results based on the monitoring of the BL Lac object Mrk 501 in the optical (B, V and R) passbands from March to May 2000. Observations spread over 12 nights were carried out using 1.2 meter Mount Abu Telescope, India and 61 cm…

Astrophysics · Physics 2009-06-23 A. C. Gupta , W. G. Deng , U. C. Joshi , J. M. Bai , M. G. Lee

Highlights of Recent Multiwavelength Observations of VHE Blazars with VERITAS

We present long-term observations of several VHE (E > 100 GeV) blazars with VERITAS, together with contemporaneous Swift and RXTE X-ray data. The observed targets include Mrk 421, Mrk 501, 1ES 2344+514. Strong flux and spectral variability…

High Energy Astrophysical Phenomena · Physics 2019-08-13 J. Grube