26 June 2011 to 1 July 2011
Montpellier, France
Europe/Paris timezone

Cosmic ray production and gamma-ray emission from Tycho's supernova remnant

28 Jun 2011, 14:55
Main amphitheater (Polytech)

Main amphitheater


Polytech Université Montpellier II


Dr Giovanni Morlino (Arcetri observatory)


We calculate the flux of non-thermal radiation from the Tycho's supernova remnant in the context of the non-linear theory of particle acceleration at shocks, which allows us to take into account self-consistently the dynamical reaction of the accelerated particles, the generation of magnetic fields in the shock proximity and the dynamical reaction of the magnetic field on the plasma. Assuming a modest acceleration efficiency we find that the strength of the magnetic field obtained as a result of streaming instability induced by cosmic rays is compatible with the interpretation of the X-ray emitting filaments being produced by strong synchrotron losses in ~300 μG magnetic fields. In such a strong magnetic field the magnetic turbulence in the upstream region of the shock can move with a speed which is a non negligible fraction of the shock speed. As a consequence the accelerated particles feel an effective compression factor less than 4 and their energy spectrum is steeper than the standard prediction, $n(E)\propto E^{-2}$. Taking into account the speed of magnetic turbulence, we consistently predict the observed gamma-ray spectrum, from the GeV band observed by FermiLAT up to the TeV band observed by VERITAS, as due to pion decay produced in hadronic collisions of a population of accelerated ions with a slope ~2.2. Remarkably the same model predict a relativistic electron population whose synchrotron emission well explain both the radio spectral index of 0.65, as well as the non-thermal X-ray emission.

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