PKS 1510-089: a rare example of a flat spectrum radio quasar with a very high-energy emission
Abstract
Context. The blazar PKS 1510-089 is an example of flat spectrum radio
quasars. High-energy emissions from this class of objects are believed to have been
produced by IC radiation with seed photons originating from the broad line region. In such
a paradigm, a lack of very high-energy emissions is expected because of the Klein-Nishina
effect and strong absorption in the broad line region. Recent detection of at least three
such blazars by Cherenkov telescopes has forced a revision of our understanding of these
objects.Aims. We have aimed to model the observed spectral energy distribution
of PKS 1510-089 from the high-energy flares in March 2009, during which very high-energy
emission were also detected by H.E.S.S.Methods. We have applied the single-zone internal shock scenario to
reproduce the multiwavelength spectrum of PKS 1510-089. We have followed the evolution of
the electrons as they propagate along the jet and emit synchrotron and IC radiation. We
have considered two sources of external photons: the dusty torus and the broad line
region. We have also examined the effects of the gamma-gamma absorption of the high-energy
photons both in the AGN environment (the broad line region and the dusty torus), as well
as while traveling over cosmological distances: the extragalactic background light.Results. We have successfully modeled the observed spectrum of PKS 1510-089. In our model, the highest energy emission is the result of the Comptonization of
the infrared photons from the dusty torus, thus avoiding Klein-Nishina regime, while the
bulk of the emissions in the GeV range may still be dominated by the Comptonization of
radiation coming from the broad line region.
Origin : Publication funded by an institution
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