The December 2009 gamma-ray flare of 3C 454.3: the multifrequency campaign
Creators: name: Pacciani, L.
name: Vittorini, V.
name: Tavani, M.
name: Fiocchi, M. T.
name: Vercellone, S.
name: D'Ammando, F.
name: Sakamoto, T.
name: Pian, E.
name: Raiteri, C. M.
name: Villata, M.
name: Sasada, M.
name: Itoh, R.
name: Yamanaka, M.
name: Uemura, M.
name: Striani, E.
name: Fugazza, D.
name: Tiengo, A.
name: Krimm, H. A.
name: Stroh, M. C.
name: Falcone, A. D.
name: Curran, P. A.
name: Sadun, A. C.
name: Lahteenmaki, A.
name: Tornikoski, M.
name: Aller, H. D.
name: Aller, M. F.
name: Lin, C. S.
name: Larionov, V. M.
name: Leto, P.
name: Takalo, L. O.
name: Berdyugin, A.
name: Gurwell, M. A.
name: Bulgarelli, A.
name: Chen, A. W.
name: Donnarumma, I.
name: Giuliani, A.
name: Longo, F.
name: Pucella, G.
name: Argan, A.
name: Caraveo, G. Barbiellini P.
name: Cattaneo, P. W.
name: Cocco, V.
name: Costa, E.
name: De Paris, G.
name: Del Monte, E.
name: Di Cocco, G.
name: Evangelista, Y.
name: Ferrari, A.
name: Feroci, M.
name: Fiorini, M.
name: Fuschino, F.
name: Galli, M.
name: Gianotti, F.
name: Labanti, C.
name: Lapshov, I.
name: Lazzarotto, F.
name: Lipari, P.
name: Marisaldi, M.
name: Mereghetti, S.
name: Morelli, E.
name: Moretti, E.
name: Morselli, A.
name: Pellizzoni, A.
name: Perotti, F.
name: Piano, G.
name: Picozza, P.
name: Pilia, M.
name: Prest, M.
name: Rapisarda, M.
name: Rappoldi, A.
name: Rubini, A.
name: Sabatini, S.
name: Soffitta, P.
name: Trifoglio, M.
name: Trois, A.
name: Vallazza, E.
name: Zanello, D.
name: Colafrancesco, S.
name: Pittori, C.
name: Verrecchia, F.
name: Santolamazza, P.
name: Lucarelli, F.
name: Giommi, P.
name: Salotti, L.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: During the month of December, 2009 the blazar 3C 454.3 became the brightest gamma-ray source in the sky, reaching a peak flux F ~2000E-8 ph/cm2/s for E &gt; 100 MeV. Starting in November, 2009 intensive multifrequency campaigns monitored the 3C 454 gamma-ray outburst. Here we report the results of a 2-month campaign involving AGILE, INTEGRAL, Swift/XRT, Swift/BAT, RossiXTE for the high-energy observations, and Swift/UVOT, KANATA, GRT, REM for the near-IR/optical/UV data. The GASP/WEBT provided radio and additional optical data. We detected a long-term active emission phase lasting ~1 month at all wavelengths: in the gamma-ray band, peak emission was reached on December 2-3, 2009. 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 broad-band spectral evolution severely constrain the theoretical modelling. We find that the pre- and post-flare broad-band behavior can be explained by a one-zone model involving SSC plus external Compton emission from an accretion disk and a broad-line region. However, the spectra of the Dec. 2-3, 2009 super-flare and of the secondary peak emission on Dec. 9, 2009 cannot be satisfactorily modelled by a simple one-zone model. An additional particle component is most likely active during these states.
description: 21 pages, 2 figures, ApJL accepted