Connecting steady emission and very high energy flaring states in blazars: the case of Mrk 421

Various attempts have been made in the literature at describing origin and physical mechanisms behind flaring events blazars with radiative emission models, but detailed properties of multi-wavelength (MWL) light curves still remain difficult to reproduce. We developed a versatile code, based on time-dependent treatment particle acceleration, escape cooling, allowing us test different scenarios connect continuous low-state self-consistently that during states. consider flares as weak perturbations quiescent state apply this description February 2010 MWL flare Mrk 421, brightest Very High Energy (VHE) ever detected from archetypal blazar, focusing interpretations minimum number free parameters. A general criterion is obtained, which disfavours one-zone model connecting low high under our assumptions. two-zone combining physically connected acceleration regions yields satisfactory interpretation available spectra although certain details The scenario finally proposed for complex VHE emitting region involves both Fermi-I Fermi-II mechanisms, respectively emission.