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

FERRARI, Attilio;
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
716
L170
L175
L. Pacciani;V. Vittorini;M. Tavani;M. T. Fiocchi;S. Vercellone;F. D'Ammando;T. Sakamoto;E. Pian;C. M. Raiteri;M. Villata;M. Sasada;R. Itoh;M. Yamanaka;M. Uemura;E. Striani;D. Fugazza;A. Tiengo;H. A. Krimm;M. C. Stroh;A. D. Falcone;P. A. Curran;A. C. Sadun;A. Lahteenmaki;M. Tornikoski;H. D. Aller;M. F. Aller;C. S. Lin;V. M. Larionov;P. Leto;L. O. Takalo;A. Berdyugin;M. A. Gurwell;A. Bulgarelli;A. W. Chen;I. Donnarumma;A. Giuliani;F. Longo;G. Pucella;A. Argan;G. Barbiellini;P. Caraveo;P. W. Cattaneo;E. Costa;G. D. Paris;E. D. Monte;G. D. Cocco;Y. Evangelista;A. Ferrari;M. Feroci;M. Fiorini;F. Fuschino;M. Galli;F. Gianotti;C. Labanti;I. Lapshov;F. Lazzarotto;P. Lipari;M. Marisaldi;S. Mereghetti;E. Morelli;E. Moretti;A. Morselli;A. Pellizzoni;F. Perotti;G. Piano;P. Picozza;M. Pilia;M. Prest;M. Rapisarda;A. Rappoldi;A. Rubini;S. Sabatini;P. Soffitta;M. Trifoglio;A. Trois;E. Vallazza;D. Zanello;S. Colafrancesco;C. Pittori;F. Verrecchia;P. Santolamazza;F. Lucarelli;P. Giommi;L. Salotti
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/86912
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