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 / 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; Longo, Francesco; 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. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 716:(2010), pp. L170-L175. [10.1088/2041-8205/716/2/L170]
The 2009 December Gamma-Ray Flare Of 3c 454.3: The Multifrequency Campaign
LONGO, FRANCESCO;
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.Pubblicazioni consigliate
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