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3C 454.3 is frequently observed in flaring state. The long term light curveof this source has been analysed with 9 year (August 2008 - July 2017) datafrom Fermi LAT detector. We have identified five flares and one quiescentstate. The flares have sub-structures with many peaks during flaring phase. Wehave estimated the rise and decay time of the flares and compared with flaresof other similar sources. The modeling of gamma ray spectral energydistributions shows in most cases Log parabola function gives the best fit tothe data. We have done time dependent leptonic modeling of two of the flares,for which simultaneous multi-wavelength data are available. These two longlasting flares Flare-2A and Flare-2D continued for 95 days and 133 daysrespectively. We have used the average values of Doppler factor, injectedluminosity in electrons, size of the emission region and the magnetic field inthe emission region in modeling these flares. The emission region is assumed tobe in the broad line region in our single zone model. The energy losses(synchrotron, synchrotron self-Compton, external Compton) and escape ofelectrons from the emission region have been included while doing themodelling. Although, the total jet powers required to model these flares withleptonic model are higher compared to other sources, they are always found tobe lower than the Eddington's luminosity of 3C 454.3. We also select someflaring peaks and show that time variation of the Doppler factor or theinjected luminosity in electrons over short time scales can explain their lightcurves.

Gamma-Ray Flares in Long Term Light Curve of 3C 454.3