During the month of 2009 December, the blazar 3C 454.3 became the brightest gamma-ray source in the sky, reaching a peak flux F similar to 2000 x 10(-8) photons cm(-2) s(-1) for E > 100 MeV. Starting in 2009 November intensive multifrequency campaigns monitored the 3C 454 gamma-ray outburst. Here, we report on the results of a two-month campaign involving AGILE, INTEGRAL, Swift/XRT, Swift/BAT, and Rossi XTE for the high-energy observations and Swift/UVOT, KANATA, Goddard Robotic Telescope, and REM for the near-IR/optical/UV data. GASP/WEBT provided radio and additional optical data. We detected a long-term active emission phase lasting similar to 1 month at all wavelengths: in the gamma-ray band, peak emission was reached on 2009 December 2-3. Remarkably, this gamma-ray super-flare was not accompanied by correspondingly intense emission in the optical/UV band that reached a level substantially lower than the previous observations in 2007-2008. The lack of strong simultaneous optical brightening during the super-flare and the determination of the broadband spectral evolution severely constrain the theoretical modeling. We find that the pre- and post-flare broadband behavior can be explained by a one-zone model involving synchrotron self-Compton plus external Compton emission from an accretion disk and a broad-line region. However, the spectra of the 2009 December 2-3 super-flare and of the secondary peak emission on 2009 December 9 cannot be satisfactorily modeled by a simple one-zone model. An additional particle component is most likely active during these states.

The 2009 december gamma-ray flare of 3C 454.3: the multifrequency campaign

PREST, MICHELA;
2010-01-01

Abstract

During the month of 2009 December, the blazar 3C 454.3 became the brightest gamma-ray source in the sky, reaching a peak flux F similar to 2000 x 10(-8) photons cm(-2) s(-1) for E > 100 MeV. Starting in 2009 November intensive multifrequency campaigns monitored the 3C 454 gamma-ray outburst. Here, we report on the results of a two-month campaign involving AGILE, INTEGRAL, Swift/XRT, Swift/BAT, and Rossi XTE for the high-energy observations and Swift/UVOT, KANATA, Goddard Robotic Telescope, and REM for the near-IR/optical/UV data. GASP/WEBT provided radio and additional optical data. We detected a long-term active emission phase lasting similar to 1 month at all wavelengths: in the gamma-ray band, peak emission was reached on 2009 December 2-3. Remarkably, this gamma-ray super-flare was not accompanied by correspondingly intense emission in the optical/UV band that reached a level substantially lower than the previous observations in 2007-2008. The lack of strong simultaneous optical brightening during the super-flare and the determination of the broadband spectral evolution severely constrain the theoretical modeling. We find that the pre- and post-flare broadband behavior can be explained by a one-zone model involving synchrotron self-Compton plus external Compton emission from an accretion disk and a broad-line region. However, the spectra of the 2009 December 2-3 super-flare and of the secondary peak emission on 2009 December 9 cannot be satisfactorily modeled by a simple one-zone model. An additional particle component is most likely active during these states.
2010
Agile; blazar; gamma-ray source; multi wavelength observation
Pacciani, Luigi; Vittorini, V; Tavani, Marco; Fiocchi, Mt; Vercellone, S; D'Ammando, F; Sakamoto, T; Pian, Elena; Raiteri, Cm; Villata, M; Sasada, M; Itoh, R; Yamanaka, M; Uemura, M; Striani, Edoardo; Fugazza, Davide; Tiengo, A; Krimm, Ha; Stroh, Mc; Falcone, Ad; Curran, Pa; Sadun, Ac; Lahteenmaki, A; Tornikoski, M; Aller, Hd; Aller, Mf; Lin, Cs; Larionov, Vm; Leto, P; Takalo, Lo; Berdyugin, A; Gurwell, Ma; Bulgarelli, A; Chen, Aw; Donnarumma, I; Giuliani, Andrea; Longo, Francesco; Pucella, Gianluca; Argan, A; Barbiellini Amidei, Guido; Caraveo, Patrizia; Cattaneo Paolo, Walter; Costa, E; De Paris, G; Del Monte, Ettore; Di Cocco, G; Evangelista, Yuri; Ferrari, A; Feroci, Marco; Fiorini, Massimiliano; Fuschino, F; Galli, M; Gianotti, F; Labanti, C; Lapshov, I; Lazzarotto, F; Lipari, Paolo; Marisaldi, M; Mereghetti, S; Morelli, Ennio; Moretti, Elena; Morselli, Aldo; Pellizzoni, A; Perotti, F; Piano, Giovanni; Picozza, Piergiorgio; Pilia, Maura; Prest, Michela; Rapisarda, Massimo; Rappoldi, Andrea; Rubini, Alda; Sabatini, Sabina; Soffitta, P; Trifoglio, M; Trois, A; Vallazza Erik, Silvio; Zanello, Dino; Colafrancesco, Sergio; Pittori, Carlotta; Verrecchia, F; Santolamazza, P; Lucarelli, Fabrizio; Giommi, P; Salotti, L.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/1737405
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