AGILE observation of a gamma-ray flare from the blazar 3C 279

A. Giuliani, F. D'Arrimando, S. Vercellone, V. Vittorini, A.W. Chen, Donnarumma, L. Pacciani, G. Pucella, A. Trois, A. Bulgarelli, F. Longo, M. Tavani, G. Tosti, D. Impiombato, A. Argan, G. Barbiellini, F. Boffelli, P.A. Caraveo, P.W. Cattaneo, V. CoccoE. Costa, E. Del Monte, G. De Paris, G. Di Cocco, Y. Evangelista, M. Feroci, M. Fiorini, F. Fornari, T. Froysland, F. Fuschino, M. Galli, F. Gianotti, C. Labanti, Y. Lapshov, F. Lazzarotto, P. Lipari, M. Marisaldi, S. Mereghetti, A. Morselli, A. Pellizzoni, F. Perotti, P. Picozza, M. Prest, M. Rapisarda, A. Rappoldi, P. Soffitta, M. Trifoglio, E. Vallazza, A. Zambra, D. Zanello, S. Cutini, D. Gasparrini, C. Pittori, B. Preger, P. Santolamazza, F. Verrecchia, P. Giommi, S. Colafrancesco, L. Salotti

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Context. We report the detection by the AGILE satellite of an intense gamma-ray flare from the gamma-ray source 3EG J1255-0549, associated with the Flat Spectrum Radio Quasar 3C 279, during the AGILE pointings towards the Virgo Region on 2007 July 9-13. Aims. The simultaneous optical, X-ray and gamma-ray covering allows us to study the spectral energy distribution (SED) and the theoretical models relative to the mid-July flaring episode. Methods. AGILE observed the source during its Science Performance Verification Phase with its two co-aligned imagers: the Gamma-Ray Imaging Detector (GRID) and the hard X-ray imager (Super-AGILE) sensitive in the 30 MeV-50 GeV and 18-60 keV respectively. During the AGILE observation the source was monitored simultaneously in the optical band by the REM telescope and in the X-ray band by the Swift satellite through 4 target of opportunity observations. Results. During 2007 July 9-13, AGILE-GRID detected gamma-ray emission from 3C 279, with the source at ∼2° from the center of the field of view, with an average flux of (2.10 ± 38) × 10-8ph cm-2s-1for energy above 100 MeV. No emission was detected, by Super-AGILE, with a 3-σ upper limit of 10 mCrab. During the observation, which lasted about 4 days, no significative gamma-ray flux variation was observed. Conclusions. The Spectral Energy Distribution is modelled with a homogeneous one-zone Synchrotron Self Compton emission plus the contributions by external Compton scattering of the direct disk radiation and, to a lesser extent, by external Compton scattering of photons from the Broad Line Region. © ESO 2009.
Original languageEnglish
Pages (from-to)509 - 513
Number of pages5
JournalAstronomy and Astrophysics
Issue number2
Publication statusPublished - Feb 2009
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Giuliani, A., D'Arrimando, F., Vercellone, S., Vittorini, V., Chen, A. W., Donnarumma, Pacciani, L., Pucella, G., Trois, A., Bulgarelli, A., Longo, F., Tavani, M., Tosti, G., Impiombato, D., Argan, A., Barbiellini, G., Boffelli, F., Caraveo, P. A., Cattaneo, P. W., ... Salotti, L. (2009). AGILE observation of a gamma-ray flare from the blazar 3C 279. Astronomy and Astrophysics, 494(2), 509 - 513.