Conferències al DAA. Xarrada a càrrec de l'investigador Michael Zacharias, del Landessternwarte Konigstuhl, Heidelberg (Alemanya). Lloc: Seminari del Departament d'Astronomia i Astrofísica, 4a planta de l'Edifici d'Investigació, a Burjassot. Dia: dijous 18 de setembre de 2014. Hora: 15:00.
Abstract:
Rapid flaring events in blazars on timescales of a few minutes challenge the standard particle evolution scenarios of jets. Most new theories that can model the fast flares, depend on the underlying assumption of a continuous injection of particles. In this talk I will present analytical calculations on a time-dependent injection scenario. Since the electrons cannot reach equilibrium for non-continuous injection, the feedback with the radiative processes causes non-linear effects inducing a much quicker cooling of the electrons. The results are manifold: The total spectral energy distributions (SEDs) exhibit unique breaks, which would otherwise be modeled with a complicated electron distribution. Fractional SEDs, which are not integrated over the entire flare, indicate the need for the knowledge of the observation time relative to the onset of the flare. Otherwise, parameters and conclusions drawn from modeling might be wrong. The lightcurves show reduced variability timescales implying less extreme parameters as in other models. Lastly, I will briefly comment on the internal photon-photon absorption. It turns out that photon-photon absorption should not be a problem for the model.
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