PACCIANI, LUIGILUIGIPACCIANI0000-0001-6897-5996VITTORINI, VALERIOVALERIOVITTORINI0000-0002-1208-8818TAVANI, MarcoMarcoTAVANI0000-0003-2893-1459FIOCCHI, MARIATERESAMARIATERESAFIOCCHI0000-0001-5697-6019VERCELLONE, STEFANOSTEFANOVERCELLONE0000-0003-1163-1396D'AMMANDO, FILIPPOFILIPPOD'AMMANDO0000-0001-7618-7527Sakamoto, T.T.SakamotoPIAN, ElenaElenaPIAN0000-0001-8646-4858RAITERI, Claudia MariaClaudia MariaRAITERI0000-0003-1784-2784VILLATA, MassimoMassimoVILLATA0000-0003-1743-6946Sasada, M.M.SasadaItoh, R.R.ItohYamanaka, M.M.YamanakaUemura, M.M.UemuraStriani, E.E.StrianiFUGAZZA, Dino PierluigiDino PierluigiFUGAZZA0000-0001-9942-277XTiengo, A.A.TiengoKrimm, H.A.H.A.KrimmStroh, M.C.M.C.StrohFalcone, A.D.A.D.FalconeCurran, P.A.P.A.CurranSadun, A.C.A.C.SadunLahteenmaki, A.A.LahteenmakiTornikoski, M.M.TornikoskiAller, H.D.H.D.AllerAller, M.F.M.F.AllerLin, C.S.C.S.LinLarionov, V.M.V.M.LarionovLETO, PAOLOPAOLOLETO0000-0003-4864-2806Takalo, L.O.L.O.TakaloBerdyugin, A.A.BerdyuginGurwell, M.A.M.A.GurwellBULGARELLI, ANDREAANDREABULGARELLI0000-0001-6347-0649Chen, A.W.A.W.ChenDonnarumma, I.I.DonnarummaGIULIANI, ANDREAANDREAGIULIANI0000-0002-4315-1699Longo, F.F.LongoPucella, G.G.PucellaARGAN, ANDREAANDREAARGAN0000-0002-6230-665XBarbiellini, G.G.BarbielliniCARAVEO, PATRIZIAPATRIZIACARAVEO0000-0003-2478-8018Cattaneo, P.W.P.W.CattaneoCOSTA, EliaEliaCOSTA0000-0002-9991-2709DE PARIS, GIACINTOGIACINTODE PARISMonte, E.D.E.D.MonteCocco, G.D.G.D.CoccoEVANGELISTA, YURIYURIEVANGELISTA0000-0001-6096-6710Ferrari, A.A.FerrariFEROCI, MARCOMARCOFEROCI0000-0002-7617-3421FIORINI, MAUROMAUROFIORINI0000-0001-8297-1983FUSCHINO, FABIOFABIOFUSCHINO0000-0003-2139-3299Galli, M.M.GalliGIANOTTI, FulvioFulvioGIANOTTI0000-0003-4666-119XLABANTI, CLAUDIOCLAUDIOLABANTI0000-0002-5086-3619Lapshov, I.I.LapshovLAZZAROTTO, FRANCESCOFRANCESCOLAZZAROTTO0000-0003-4871-4072Lipari, P.P.LipariMARISALDI, MARTINOMARTINOMARISALDI0000-0002-4000-3789MEREGHETTI, SandroSandroMEREGHETTI0000-0003-3259-7801Morelli, E.E.MorelliMoretti, E.E.MorettiMorselli, A.A.MorselliPELLIZZONI, ALBERTO PAOLOALBERTO PAOLOPELLIZZONI0000-0002-4590-0040Perotti, F.F.PerottiPIANO, GiovanniGiovanniPIANO0000-0002-9332-5319Picozza, P.P.PicozzaPILIA, MauraMauraPILIA0000-0001-7397-8091Prest, M.M.PrestRapisarda, M.M.RapisardaRappoldi, A.A.RappoldiRubini, A.A.RubiniSabatini, S.S.SabatiniSOFFITTA, PAOLOPAOLOSOFFITTA0000-0002-7781-4104TRIFOGLIO, MASSIMOMASSIMOTRIFOGLIO0000-0002-2505-3630TROIS, ALESSIOALESSIOTROIS0000-0002-3180-6002Vallazza, E.E.VallazzaZanello, D.D.ZanelloColafrancesco, S.S.ColafrancescoPITTORI, CarlottaCarlottaPITTORI0000-0001-6661-9779VERRECCHIA, FrancescoFrancescoVERRECCHIA0000-0003-3455-5082Santolamazza, P.P.SantolamazzaLUCARELLI, FabrizioFabrizioLUCARELLI0000-0002-6311-764XGiommi, P.P.GiommiSalotti, L.L.Salotti2023-01-242023-01-2420102041-8205http://hdl.handle.net/20.500.12386/33021During the month of 2009 December, the blazar 3C 454.3 became the brightest gamma-ray source in the sky, reaching a peak flux F 2000 × 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 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. The American Astronomical Society. All rights reserved.STAMPAenArticle10.1088/2041-8205/716/2/L1702-s2.0-77956736221https://iopscience.iop.org/article/10.1088/2041-8205/716/2/L170http://www.scopus.com/inward/record.url?eid=2-s2.0-77956736221&partnerID=MN8TOARS2010ApJ...716L.170PFIS/05 - ASTRONOMIA E ASTROFISICA