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 / Pacciani L; Vittorini V; Tavani M; Fiocchi MT; Vercellone S; DAmmando F; Sakamoto T; Pian E; Raiteri CM; Villata M; Sasada M; Itoh R; Yamanaka M; Uemura M; Striani E; Fugazza D; 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 A; Longo F; Pucella G; Argan A; Barbiellini G; Caraveo P; Cattaneo PW; Costa E; De Paris G; Del Monte E; Di Cocco G; Evangelista Y; Ferrari A; Feroci M; Fiorini M; Fuschino F; Galli M; Gianotti F; Labanti C; Lapshov I; Lazzarotto F; Lipari P; Marisaldi M; Mereghetti S; Morelli E; Moretti E; Morselli A; Pellizzoni A; Perotti F; Piano G; Picozza P; Pilia M; Prest M; Rapisarda M; Rappoldi A; Rubini A; Sabatini S; Soffitta P; Trifoglio M; Trois A; Vallazza E; Zanello D; Colafrancesco S; Pittori C; Verrecchia F; Santolamazza P; Lucarelli F; Giommi P; Salotti L. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 716:2(2010), pp. 170-175. [10.1088/2041-8205/716/2/L170]
THE 2009 DECEMBER GAMMA-RAY FLARE OF 3C 454.3: THE MULTIFREQUENCY CAMPAIGN
D'AMMANDO, FILIPPO;
2010
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
