Related papers: The Surprising Crab Nebula

Discovery of Variability in the Very High Energy Gamma-Ray Emission of 1ES 1218+304 with VERITAS

We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ~6% of the…

High Energy Astrophysical Phenomena · Physics 2010-01-18 The VERITAS Collaboration , V. A. Acciari , E. Aliu , M. Beilicke , W. Benbow , D. Boltuch , M. Böttcher , S. M. Bradbury , V. Bugaev , K. Byrum , A. Cesarini , L. Ciupik , P. Cogan , W. Cui , R. Dickherber , C. Duke , A. Falcone , J. P. Finley , G. Finnegan , L. Fortson , A. Furniss , N. Galante , D. Gall , K. Gibbs , R. Guenette , G. H. Gillanders , S. Godambe , J. Grube , D. Hanna , C. M. Hui , T. B. Humensky , A. Imran , P. Kaaret , N. Karlsson , M. Kertzman , D. Kieda , H. Krawczynski , F. Krennrich , M. J. Lang , S. LeBohec , G. Maier , S. McArthur , A. McCann , P. Moriarty , T. Nagai , R. A. Ong , A. N. Otte , D. Pandel , J. S. Perkins , A. Pichel , M. Pohl , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , E. Roache , H. J. Rose , M. Schroedter , G. H. Sembroski , A. W. Smith , D. Steele , S. P. Swordy , M. Theiling , S. Thibadeau , V. V. Vassiliev , S. Vincent , S. P. Wakely , T. C. Weekes , A. Weinstein , T. Weisgarber , D. A. Williams

A multi-wavelength study to decipher the 2017 flare of the blazar OJ 287

In February 2017, the blazar OJ~287 underwent a period of intense multiwavelength activity. It reached a new historic peak in the soft X-ray (0.3-10 keV) band, as measured by Swift-XRT. This event coincides with a very-high-energy (VHE)…

High Energy Astrophysical Phenomena · Physics 2024-08-28 A. Acharyya , C. B. Adams , A. Archer , P. Bangale , J. T. Bartkoske , P. Batista , W. Benbow , A. Brill , J. P. Caldwell , M. Carini , J. L. Christiansen , A. J. Chromey , M. Errando , A. Falcone , Q. Feng , J. P. Finley , J. Foote , L. Fortson , A. Furniss , G. Gallagher , W. Hanlon , D. Hanna , O. Hervet , C. E. Hinrichs , J. Hoang , J. Holder , T. B. Humensky , W. Jin , M. N. Johnson , P. Kaaret , M. Kertzman , M. Kherlakian , D. Kieda , T. K. Kleiner , N. Korzoun , F. Krennrich , S. Kumar , M. J. Lang , M. Lundy , G. Maier , C. EMcGrath , M. J. Millard , J. Millis , C. L. Mooney , P. Moriarty , R. Mukherjee , S. O'Brien , R. A. Ong , M. Pohl , E. Pueschel , J. Quinn , P. L. Rabinowitz , K. Ragan , P. T. Reynolds , D. Ribeiro , E. Roache , J. L. Ryan , I. Sadeh , A. C. Sadun , L. Saha , M. Santander , G. H. Sembroski , K. Shahinyan , R. Shang , M. Splettstoesser , D. Tak , A. K. Talluri , J. V. Tucci , D. A. Williams , S. L. Wong , S. G. Jorstad , R. Lico , P. Lusen , A. P. Marscher

A Three-Year Multi-Wavelength Study of the Very High Energy Gamma-ray Blazar 1ES 0229+200

The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Gamma ~ 2.5), very-high-energy-emitting (E > 100 GeV) gamma-ray blazar. Very-high-energy measurements of this active galactic…

High Energy Astrophysical Phenomena · Physics 2015-06-18 E. Aliu , S. Archambault , T. Arlen , T. Aune , B. Behera , M. Beilicke , W. Benbow , K. Berger , R. Bird , A. Bouvier , J. H. Buckley , V. Bugaev , K. Byrum , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , C. Duke , J. Dumm , M. Errando , A. Falcone , S. Federici , Q. Feng , J. P. Finley , H. Fleischhack , P. Fortin , L. Fortson , A. Furniss , N. Galante , G. H. Gillanders , S. Griffin , S. T. Griffiths , J. Grube , G. Gyuk , D. Hanna , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , M. Kertzman , Y. Khassen , D. Kieda , H. Krawczynski , F. Krennrich , M. J. Lang , A. S Madhavan , G. Maier , P. Majumdar , S. McArthur , A. McCann , K. Meagher , J. Millis , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faolain de Bhroithe , R. A. Ong , A. N. Otte , N. Park , J. S. Perkins , M. Pohl , A. Popkow , H. Prokoph , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , G. T. Richards , E. Roache , G. H. Sembroski , A. W. Smith , D. Staszak , I. Telezhinsky , M. Theiling , A. Varlotta , V. V. Vassiliev , S. Vincent , S. P. Wakely , T. C. Weekes , A. Weinstein , R. Welsing , D. A. Williams , A. Zajczyk , B. Zitzer

1997 October Event(s) in the Crab Pulsar

In October 1997 daily monitoring observations of the Crab pulsar at 327 MHz and 610 MHz with an 85ft telescope in Green Bank, WV showed a jump in the dispersion by 0.12 cm^{-3} pc. Pulses were seen simultaneously at both old and new…

Astrophysics · Physics 2016-08-30 D. C. Backer

Time evolution of the X-ray and gamma-ray fluxes of the Crab pulsar

We studied the evolution of the X-ray and gamma-ray spectra of the Crab pulsar utilizing the 11-year observations from the Rossi X-ray Timing Explorer (RXTE) and 9-year observations from the Fermi Gamma-ray Space Telescope (FGST). By…

High Energy Astrophysical Phenomena · Physics 2018-10-10 L. L. Yan , M. Y. Ge , F. J. Lu , S. J. Zheng , Y. L. Tuo , Z. J. Li , L. M. Song , J. L. Qu

The Nature of $\gamma$-ray Variability in Blazars

We present an in-depth and systematic variability study of a sample of 20 powerful blazars, including 12 BL Lacs and 8 flat spectrum radio quasars, applying various analysis tools such as flux distribution, symmetry analysis, and time…

High Energy Astrophysical Phenomena · Physics 2020-03-18 Gopal Bhatta , Niraj Dhital

Multi-wavelength observations of the Blazar 4C +28.07

The active galactic nucleus 4C +28.07 is a flat spectrum radio quasar, one of the brightest at $\gamma$-ray energies. We study its multi-wavelength emission by analysing $\sim12.3$ years of \textit{Fermi-LAT} data in the $\gamma$-ray band…

High Energy Astrophysical Phenomena · Physics 2022-01-10 Davit Zargaryan , Jonathan Mackey , Thibault Barnouin , Felix Aharonian

The Brightest Pulses in the Universe: Multifrequency Observations of the Crab Pulsar's Giant Pulses

We analyze the Crab pulsar at ten frequencies from 0.43 to 8.8 GHz using data obtained at the Arecibo Observatory. Giant pulses occur only in the main and interpulse components manifest from radio frequencies to gamma-ray energies.…

Astrophysics · Physics 2009-11-07 J. M. Cordes , N. D. R. Bhat , T. H. Hankins , M. A. McLaughlin , J. Kern

Modeling of the gamma-ray pulsed spectra of Geminga, Crab, and Vela with synchro-curvature radiation

$\gamma$-ray spectra of pulsars have been mostly studied in a phenomenological way, by fitting them to a cut-off power-law function. Here, we analyze a model where pulsed emission comes from synchro-curvature processes in a gap. We…

High Energy Astrophysical Phenomena · Physics 2015-06-24 Daniele Viganò , Diego F. Torres

An investigation of flare emissions at multiple wavelengths

We report multi-wavelength observations of four solar flares on 2014 July 07. We firstly select these flares according to the soft X-ray (SXR) and extreme ultraviolet (EUV) emissions recorded by the Extreme Ultraviolet Variability…

Solar and Stellar Astrophysics · Physics 2021-05-05 Dong Li , Alexander Warmuth , Lei Lu , Zongjun Ning

Discovery of very high-energy gamma-ray emission from the LBL object BL Lacertae

The low-frequency peaked BL Lac (LBL) object BL Lacertae was observed with the MAGIC telescope from 2005 August to December (22.2 hr), and from 2006 July to September (26.0 hr). A very high energy (VHE) gamma-ray signal was discovered with…

Astrophysics · Physics 2007-09-17 MAGIC Collaboration , M. Hayashida , K. Berger , E. Lindfors , V. Vitale , R. Wagner , E. Lorenz

Multiwavelength Variability Analysis of Fermi-LAT Blazars

Blazars present highly variable $\gamma$-ray emission. This variability, which can range from a few minutes to several years, is also observed at other wavelengths across the entire electromagnetic spectrum. We make use of the first 12…

High Energy Astrophysical Phenomena · Physics 2024-03-05 P. Peñil , J. Otero-Santos , M. Ajello , S. Buson , A. Domínguez , L. Marcotulli , N. Torres-Albà , J. Becerra González , J. A. Acosta-Pulido

H.E.S.S. Observations of PKS 2155-304

The high-frequency peaked BL Lac PKS 2155-304 at redshift z=0.117 has been detected with high significance (~45 sigma) at energies greater than 160 GeV, using the H.E.S.S. stereoscopic array of imaging air-Cherenkov telescopes in Namibia. A…

Astrophysics · Physics 2012-08-27 The H. E. S. S. Collaboration , : , F. Aharonian

Radio to gamma-ray variability study of blazar S5 0716+714

We present the results of a series of radio, optical, X-ray and gamma-ray observations of the BL Lac object S50716+714 carried out between April 2007 and January 2011. The multi-frequency observations were obtained using several ground and…

High Energy Astrophysical Phenomena · Physics 2015-06-12 B. Rani , T. P. Krichbaum , L. Fuhrmann , M. Boettcher , B. Lott , H. D. Aller , M. F. Aller , E. Angelakis , U. Bach , D. Bastieri , A. D. Falcone , Y. Fukazawa , K. E. Gabanyi , A. C. Gupta , M. Gurwell , R. Itoh , K. S. Kawabata , M. Krips , A. A. Lähteenmäki , X. Liu , N. Marchili , W. Max-Moerbeck , I. Nestoras , E. Nieppola , G. Quintana-Lacaci , A. C. S. Readhead , J. L. Richards , M. Sasada , A. Sievers , K. Sokolovsky , M. Stroh , J. Tammi , M. Tornikoski , M. Uemura , H. Ungerechts , T. Urano , J. A. Zensus

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab pulsar and the surrounding nebula powered by the pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind is a bright source of gamma-rays carrying crucial information about this…

High Energy Astrophysical Phenomena · Physics 2021-11-15 The LHAASO Collaboration , Zhen Cao , F. Aharonian , Q. An , Axikegu , L. X. Bai , Y. X. Bai , Y. W. Bao , D. Bastieri , X. J. Bi , Y. J. Bi , H. Cai , J. T. Cai , Zhe Cao , J. Chang , J. F. Chang , B. M. Chen , E. S. Chen , J. Chen , Liang Chen , Liang Chen , Long Chen , M. J. Chen , M. L. Chen , Q. H. Chen , S. H. Chen , S. Z. Chen , T. L. Chen , X. L. Chen , Y. Chen , N. Cheng , Y. D. Cheng , S. W. Cui , X. H. Cui , Y. D. Cui , B. D'Ettorre Piazzoli , B. Z. Dai , H. L. Dai , Z. G. Dai , Danzengluobu , D. della Volpe , X. J. Dong , K. K. Duan , J. H. Fan , Y. Z. Fan , Z. X. Fan , J. Fang , K. Fang , C. F. Feng , L. Feng , S. H. Feng , Y. L. Feng , B. Gao , C. D. Gao , L. Q. Gao , Q. Gao , W. Gao , M. M. Ge , L. S. Geng , G. H. Gong , Q. B. Gou , M. H. Gu , F. L. Guo , J. G. Guo , X. L. Guo , Y. Q. Guo , Y. Y. Guo , Y. A. Han , H. H. He , H. N. He , J. C. He , S. L. He , X. B. He , Y. He , M. Heller , Y. K. Hor , C. Hou , X. Hou , H. B. Hu , S. Hu , S. C. Hu , X. J. Hu , D. H. Huang , Q. L. Huang , W. H. Huang , X. T. Huang , X. Y. Huang , Z. C. Huang , F. Ji , X. L. Ji , H. Y. Jia , K. Jiang , Z. J. Jiang , C. Jin , T. Ke , D. Kuleshov , K. Levochkin , B. B. Li , Cheng Li , Cong Li , F. Li , H. B. Li , H. C. Li , H. Y. Li , Jie Li , Jian Li , K. Li , W. L. Li , X. R. Li , Xin Li , Xin Li , Y. Li , Y. Z. Li , Zhe Li , Zhuo Li , E. W. Liang , Y. F. Liang , S. J. Lin , B. Liu , C. Liu , D. Liu , H. Liu , H. D. Liu , J. Liu , J. L. Liu , J. S. Liu , J. Y. Liu , M. Y. Liu , R. Y. Liu , S. M. Liu , W. Liu , Y. Liu , Y. N. Liu , Z. X. Liu , W. J. Long , R. Lu , H. K. Lv , B. Q. Ma , L. L. Ma , X. H. Ma , J. R. Mao , A. Masood , Z. Min , W. Mitthumsiri , T. Montaruli , Y. C. Nan , B. Y. Pang , P. Pattarakijwanich , Z. Y. Pei , M. Y. Qi , Y. Q. Qi , B. Q. Qiao , J. J. Qin , D. Ruffolo , V. Rulev , A. Sáiz , L. Shao , O. Shchegolev , X. D. Sheng , J. Y. Shi , H. C. Song , Yu. V. Stenkin , V. Stepanov , Y. Su , Q. N. Sun , X. N. Sun , Z. B. Sun , P. H. T. Tam , Z. B. Tang , W. W. Tian , B. D. Wang , C. Wang , H. Wang , H. G. Wang , J. C. Wang , J. S. Wang , L. P. Wang , L. Y. Wang , R. N. Wang , Wei Wang , Wei Wang , X. G. Wang , X. J. Wang , X. Y. Wang , Y. Wang , Y. D. Wang , Y. J. Wang , Y. P. Wang , Z. H. Wang , Z. X. Wang , Zhen Wang , Zheng Wang , D. M. Wei , J. J. Wei , Y. J. Wei , T. Wen , C. Y. Wu , H. R. Wu , S. Wu , W. X. Wu , X. F. Wu , S. Q. Xi , J. Xia , J. J. Xia , G. M. Xiang , D. X. Xiao , G. Xiao , H. B. Xiao , G. G. Xin , Y. L. Xin , Y. Xing , D. L. Xu , R. X. Xu , L. Xue , D. H. Yan , J. Z. Yan , C. W. Yang , F. F. Yang , J. Y. Yang , L. L. Yang , M. J. Yang , R. Z. Yang , S. B. Yang , Y. H. Yao , Z. G. Yao , Y. M. Ye , L. Q. Yin , N. Yin , X. H. You , Z. Y. You , Y. H. Yu , Q. Yuan , H. D. Zeng , T. X. Zeng , W. Zeng , Z. K. Zeng , M. Zha , X. X. Zhai , B. B. Zhang , H. M. Zhang , H. Y. Zhang , J. L. Zhang , J. W. Zhang , L. X. Zhang , Li Zhang , Lu Zhang , P. F. Zhang , P. P. Zhang , R. Zhang , S. R. Zhang , S. S. Zhang , X. Zhang , X. P. Zhang , Y. F. Zhang , Y. L. Zhang , Yi Zhang , Yong Zhang , B. Zhao , J. Zhao , L. Zhao , L. Z. Zhao , S. P. Zhao , F. Zheng , Y. Zheng , B. Zhou , H. Zhou , J. N. Zhou , P. Zhou , R. Zhou , X. X. Zhou , C. G. Zhu , F. R. Zhu , H. Zhu , K. J. Zhu , X. Zuo

Light-curve instabilities of Beta Lyrae observed by the BRITE satellites

Photometric instabilities of $\beta$ Lyr were observed in 2016 by two red-filter BRITE satellites over more than 10 revolutions of the binary, with $\sim$100-minute sampling. Analysis of the time series shows that flares or fading events…

Solar and Stellar Astrophysics · Physics 2018-06-27 Slavek M. Rucinski , Andrzej Pigulski , Adam Popowicz , Rainer Kuschnig , Szymon Kozłowski , Anthony F. J. Moffat , Krešimir Pavlovski , Gerald Handler , H. Pablo , G. A. Wade , Werner W. Weiss , Konstanze Zwintz

Characterizing Gamma-Radio Delayed Flaring Activity from Blazars

Flaring activity from the jets of active galactic nuclei has been studied for several decades, closely related to the loading and evolution of the jet. In this work, we focus on the sub-hundred parsec jet region, well traced by non-thermal…

High Energy Astrophysical Phenomena · Physics 2026-04-07 Alina Kochocki , Emma Kun , Sam Hori

AGILE detection of extreme gamma-ray activity from the blazar PKS 1510-089 during March 2009. Multifrequency analysis

We report on the extreme gamma-ray activity from the FSRQ PKS 1510-089 observed by AGILE in March 2009. In the same period a radio-to-optical monitoring of the source was provided by the GASP-WEBT and REM. Moreover, several Swift ToO…

High Energy Astrophysical Phenomena · Physics 2011-06-16 F. D'Ammando , C. M. Raiteri , M. Villata , P. Romano , G. Pucella , H. A. Krimm , S. Covino , M. Orienti , G. Giovannini , S. Vercellone , E. Pian , I. Donnarumma , V. Vittorini , M. Tavani , 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 , Y. Evangelista , M. Feroci , A. Ferrari , M. Fiorini , T. Froysland , M. Frutti , 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 , G. Piano , P. Picozza , M. Pilia , G. Porrovecchio , M. Prest , M. Rapisarda , A. Rappoldi , A. Rubini , S. Sabatini , P. Soffitta , E. Striani , M. Trifoglio , A. Trois , E. Vallazza , A. Zambra , D. Zanello , I. Agudo , H. D. Aller , M. F. Aller , A. A. Arkharov , U. Bach , E. Benitez , A. Berdyugin , D. A. Blinov , C. S. Buemi , W. P. Chen , A. Di Paola , M. Dolci , E. Forne , L. Fuhrmann , J. L. Gomez , M. A. Gurwell , B. Jordan , S. G. Jorstad , J. Heidt , D. Hiriart , T. Hovatta , H. Y. Hsiao , G. Kimeridze , T. S. Konstantinova , E. N. Kopatskaya , E. Koptelova , O. M. Kurtanidze , S. O. Kurtanidze , V. M. Larionov , A. Lahteenmaki , P. Leto , E. Lindfors , A. P. Marscher , B. McBreen , I. M. McHardy , D. A. Morozova , K. Nilsson , M. Pasanen , M. Roca-Sogorb , A. Sillanpaa , L. O. Takalo , M. Tornikoski , C. Trigilio , I. S. Troitsky , G. Umana , L. A. Antonelli , S. Colafrancesco , C. Pittori , P. Santolamazza , F. Verrecchia , P. Giommi , L. Salotti

A Spectacular VHE Gamma-Ray Outburst from PKS 2155-304 in 2006

Since 2002 the VHE (>100 GeV) gamma-ray flux of the high-frequency peaked BL Lac PKS 2155-304 has been monitored with the High Energy Stereoscopic System (HESS). An extreme gamma-ray outburst was detected in the early hours of July 28, 2006…

Astrophysics · Physics 2007-10-01 W. Benbow , C. Boisson , L. Costamante , O. de Jager , G. Dubus , D. Emmanoulopoulos , B. Giebels , S. Pita , M. Punch , C. Raubenheimer , M. Raue , H. Sol , S. Wagner

MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

The high-frequency-peaked BL Lac (HBL) 1ES 0806+524 (z = 0.138) was discovered in VHE $\gamma$ rays in 2008. Until now, the broad-band spectrum of 1ES 0806+524 has been only poorly characterized, in particular at high energies. We analysed…

Astrophysics of Galaxies · Physics 2019-08-13 MAGIC Collaboration , J. Aleksić , S. Ansoldi , L. A. Antonelli , P. Antoranz , A. Babic , P. Bangale , J. A. Barrio , J. Becerra González , W. Bednarek , E. Bernardini , B. Biasuzzi , A. Biland , O. Blanch , S. Bonnefoy , G. Bonnoli , F. Borracci , T. Bretz , E. Carmona , A. Carosi , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Da Vela , F. Dazzi , A. De Angelis , G. De Caneva , B. De Lotto , E. de O. na Wilhelmi , C. Delgado Mendez , F. Di Pierro , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Eisenacher , D. Elsaesser , A. Fernández-Barral , D. Fidalgo , M. V. Fonseca , L. Font , K. Frantzen , C. Fruck , D. Galindo , R. J. García López , M. Garczarczyk , D. Garrido Terrats , M. Gaug , N. Godinović , A. González Mu. noz , S. R. Gozzini , D. Hadasch , Y. Hanabata , M. Hayashida , J. Herrera , J. Hose , D. Hrupec , W. Idec , V. Kadenius , H. Kellermann , M. L. Knoetig , K. Kodani , Y. Konno , J. Krause , H. Kubo , J. Kushida , A. La Barbera , D. Lelas , N. Lewandowska , E. Lindfors , S. Lombardi , F. Longo , M. López , R. López-Coto , A. López-Oramas , E. Lorenz , I. Lozano , M. Makariev , K. Mallot , G. Maneva , K. Mannheim , L. Maraschi , B. Marcote , M. Mariotti , M. Martínez , D. Mazin , U. Menzel , J. M. Miranda , R. Mirzoyan , A. Moralejo , P. Munar-Adrover , D. Nakajima , V. Neustroev , A. Niedzwiecki , M. Nievas Rosillo , K. Nilsson , K. Nishijima , K. Noda , R. Orito , A. Overkemping , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , X. Paredes-Fortuny , M. Persic , J. Poutanen , P. G. Prada Moroni , E. Prandini , I. Puljak , R. Reinthal , W. Rhode , M. Ribó , J. Rico , J. Rodriguez Garcia , T. Saito , K. Saito , K. Satalecka , V. Scalzotto , V. Scapin , C. Schultz , T. Schweizer , S. N. Shore , A. Sillanpää , J. Sitarek , I. Snidaric , D. Sobczynska , A. Stamerra , T. Steinbring , M. Strzys , L. Takalo , H. Takami , F. Tavecchio , P. Temnikov , T. Terzić , D. Tescaro , M. Teshima , J. Thaele , D. F. Torres , T. Toyama , A. Treves , P. Vogler , M. Will , R. Zanin , K. Berger , S. Buson , F. D'Ammando , D. Gasparrini , T. Hovatta , W. Max-Moerbeck , A. Readhead , J. Richards