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Related papers: Gamma-ray blazars: the view from AGILE

200 papers

3C 454.3 is the most variable and intense extragalactic gamma-ray blazar detected by AGILE and Fermi during the last 4 years. This remarkable source shows extreme flux variability (about a fact or of 20) on a time-scale of 24-48 hours, as…

High Energy Astrophysical Phenomena · Physics 2019-08-14 S. Vercellone

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…

Blazars are a highly-variable, radio-loud subclass of active galactic nuclei (AGN). In order to better understand such objects we must be able to easily identify candidate blazars from the growing population of unidentified sources. Working…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Philip S. Cowperthwaite , F. Massaro , R. D'Abrusco , A. Paggi , G. Tosti , Howard A. Smith

We report on a systematic search for hard X-ray and gamma-ray emission in coincidence with fast radio bursts (FRBs) observed by the AGILE satellite. We used 13 years of AGILE archival data searching for time coincidences between exposed…

Aims. The observation of gamma -ray flares from blazar 0836+710 in 2011, following a period of quiescence, offered an opportunity to study correlated activity at different wavelengths for a high-redshift (z=2.218) active galactic nucleus.…

High Energy Astrophysical Phenomena · Physics 2015-06-16 A. Akyuz , D. J. Thompson , D. Donato , J. S. Perkins , L. Fuhrmann , E. Angelakis , J. A. Zensus , S. Larsson , K. Sokolovsky , O. Kurtanidze

The BL Lacertae object 3C 66A was detected in a flaring state by the Fermi Large Area Telescope (LAT) and VERITAS in 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, and Chandra…

The AGILE satellite detected several episodes of transient gamma-ray emission from Cygnus X-3. Cross-correlating the AGILE light curve with both X-ray and radio monitoring data, we found that the main events of gamma-ray activity were…

High Energy Astrophysical Phenomena · Physics 2019-08-14 G. Piano , M. Tavani , V. Vittorini , A. Giuliani

Blazars are a small fraction of all extragalactic sources but, unlike other objects, they are strong emitters across the entire electromagnetic spectrum. Recent data in the microwave region of the electromagnetic spectrum have become…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-24 D. Gasparrini , E. Cavazzuti , P. Giommi , C. Pittori , S. Colafrancesco , Fermi-LAT collaboration

AGILE data on Cygnus X-3 are reviewed focussing on the correlation between the production of gamma-ray transient emission and spectral state changes of the source. AGILE clearly establishes a relation between enhanced gamma-ray emission and…

High Energy Astrophysical Phenomena · Physics 2019-08-15 G. Piano , A. Bulgarelli , M. Tavani , V. Vittorini , M. McCollough , G. Pooley , S. Trushkin

Violent multi-wavelength variabilities are observed in gamma-ray-selected blazars. We present an analysis of long-term light curves for eight bright blazars to explore the co-variation pattern in the gamma-ray and radio bands. We extract…

High Energy Astrophysical Phenomena · Physics 2020-05-27 Hai-Ming Zhang , Zhen-Jie Wang , Jin Zhang , Ting-Feng Yi , Liang Chen , Rui-Jing Lu , En-Wei Liang

The blazar 3C 454.3 was revealed by the Fermi Gamma-ray Space Telescope to be in an exceptionally high flux state in July 2008. Accordingly, we performed a multi-wavelength monitoring campaign on this blazar using IR and optical…

Astrophysics · Physics 2011-02-11 E. W. Bonning , C. Bailyn , C. M. Urry , M. Buxton , G. Fossati , L. Maraschi , P. Coppi , R. Scalzo , J. Isler , A. Kaptur

The AGILE $\gamma$-ray telescope (Tavani et al. 1998) will have a relatively uniform sensitivity over a very wide field of view. This allows to simultaneously monitor several AGN's and to react quickly with multiwavelength observations in…

Astrophysics · Physics 2007-05-23 S. Mereghetti

For more than 15 years, since the days of the Energetic Gamma-Ray Experiment Telescope (EGRET) on board the Compton Gamma-Ray Observatory (CGRO; 1991-2000), it has remained an open question why the prominent blazar 3C 345 was not reliably…

We report the Astrorivelatore Gamma ad Immagini LEggero (AGILE) observations of solar flares, detected by the on board anticoincidence system in the 80-200 keV energy range, from 2007 May 1st to 2022 August 31st. In more than 15 yr, AGILE…

The blazar 3C 279, one of the brightest identified extragalactic objects in the gamma-ray sky, underwent a flare of a factor 10 amplitude in gamma-rays towards the end of a 3-week pointing by CGRO, in 1996 January-February. The flare peak…

Astrophysics · Physics 2009-10-30 A. E. Wehrle , E. Pian , C. M. Urry , L. Maraschi , G. Ghisellini , R. C. Hartman

AGILE pointed observations performed from July 9, 2007 to October 30, 2009 cover a very large time interval, with a \gamma-ray dataset useful to perform studies of medium to high brightness galactic sources in the 30 MeV -- 50 GeV energy…

High Energy Astrophysical Phenomena · Physics 2019-08-13 F. Verrecchia , C. Pittori , A. Bulgarelli , A. W. Chen , M. Tavani , F. Lucarelli , P. Giommi

We report first results of a multifrequency campaign from radio to hard X-ray energies of the prominent gamma-ray blazar 3C 279 during the first year of the INTEGRAL mission. The variable blazar was found at a low activity level, but was…

We searched for gamma-ray blazar candidates among the 382 unidentified hard X-ray sources of the 3rd Palermo BAT Catalog (3PBC) obtained from the analysis of 66 months of SWIFT-BAT survey data and listing 1586 sources. We adopted a recently…

High Energy Astrophysical Phenomena · Physics 2015-06-16 A. Maselli , F. Massaro , G. Cusumano , R. D'Abrusco , V. La Parola , A. Paggi , A. Segreto , Howard A. Smith , G. Tosti

Among the blazars whose emission has been detected up to very-high-energy (VHE; 100 GeV < E < 100 TeV) gamma rays, intermediate synchrotron-peaked BL Lacs (IBLs) are quite rare. The IBL B2 1811+31 (z = 0.117) exhibited intense flaring…

High Energy Astrophysical Phenomena · Physics 2025-05-23 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 , A. Babic , U. Barres de Almeida , J. A. Barrio , L. Barrios-Jimenez , I. Batkovic , J. Baxter , J. Becerra Gonzalez , 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 , A. Chilingarian , A. Cifuentes , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , F. D'Ammando , G. D'Amico , 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 , A. Dinesh , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , L. Eisenberger , D. Elsaesser , J. Escudero , L. Farina , L. Foffano , L. Font , S. Frose , Y. Fukazawa , R. J. Garcia Lopez , 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. Gunther , D. Hadasch , A. Hahn , T. Hassan , L. Heckmann , J. Herrera Llorente , D. Hrupec , R. Imazawa , D. Israyelyan , T. Itokawa , I. Jimenez Martinez , J. Jimenez Quiles , J. Jormanainen , S. Kankkunen , T. Kayanoki , D. Kerszberg , M. Khachatryan , G. W. Kluge , Y. Kobayashi , J. Konrad , P. M. Kouch , H. Kubo , J. Kushida , M. Lainez , A. Lamastra , E. Lindfors , S. Lombardi , F. Longo , R. Lopez-Coto , M. Lopez-Moya , A. Lopez-Oramas , S. Loporchio , A. Lorini , L. Lulic , E. Lyard , P. Majumdar , M. Makariev , G. Maneva , M. Manganaro , S. Mangano , K. Mannheim , M. Mariotti , M. Martinez , P. Maruševec , A. Mas-Aguilar , D. Mazin , S. Menchiari , S. Mender , D. Miceli , J. M. Miranda , R. Mirzoyan , M. Molero Gonzalez , E. Molina , H. A. Mondal , A. Moralejo , T. Nakamori , C. Nanci , V. Neustroev , L. Nickel , M. Nievas Rosillo , C. Nigro , L. Nikolic , K. Nilsson , K. Nishijima , T. Njoh Ekoume , K. Noda , S. Nozaki , A. Okumura , S. Paiano , D. Paneque , R. Paoletti , J. M. Paredes , L. Pavletic , M. Peresano , M. Persic , M. Pihet , G. Pirola , F. Podobnik , P. G. Prada Moroni , E. Prandini , G. Principe , W. Rhode , M. Ribo , J. Rico , C. Righi , N. Sahakyan , T. Saito , F. G. Saturni , K. Schmitz , F. Schmuckermaier , J. L. Schubert , A. Sciaccaluga , G. Silvestri , J. Sitarek , V. Sliusar , D. Sobczynska , A. Stamerra , J. Striškovic , D. Strom , M. Strzys , Y. Suda , H. Tajima , M. Takahashi , R. Takeishi , P. Temnikov , K. Terauchi , T. Terzic , M. Teshima , A. Tutone , S. Ubach , J. van Scherpenberg , M. Vazquez Acosta , S. Ventura , G. Verna , I. Viale , A. Vigliano , C. F. Vigorito , V. Vitale , I. Vovk , R. Walter , F. Wersig , M. Will , T. Yamamoto , C. Bartolini , E. Bissaldi , S. Garrappa , E. Ankara , N. Bader , M. Feige , F. Hümmer , F. Kaplan , C. Lorey , D. Reinhart , K. Schoch , R. Steineke , A. Marchini , V. Fallah Ramazani , M. J. Graham , T. Hovatta , S. Kiehlmann , A. C. S. Readhead , P. Benke , F. Eppel , S. Hammeric , J. Heßdörfer , M. Kadler , D. Kirchner , A. Gokus , G. F. Paraschos , F. Rösch , J. Sinapius

We present the gamma-ray data of the extraordinary flaring activity above 100 MeV from the flat spectrum radio quasar 3C 454.3 detected by AGILE during the month of December 2009. 3C 454.3, that has been among the most active blazars of the…