A local fading accelerator and the origin of TeV cosmic ray electrons. (arXiv:1811.07551v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Recchia_S/0/1/0/all/0/1">S. Recchia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gabici_S/0/1/0/all/0/1">S. Gabici</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aharonian_F/0/1/0/all/0/1">F. A. Aharonian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vink_J/0/1/0/all/0/1">J. Vink</a>
The total cosmic ray electron spectrum (electrons plus positrons) exhibits a
break at a particle energy of $sim 1rm~TeV$ and extends without any
attenuation up to $rm sim 20~ TeV $. Synchrotron and inverse Compton energy
losses strongly constrain both the age and the distance of the potential
sources of TeV and multi-TeV electrons to $rmapprox 10^5~yr$ and $rm approx
100-500~pc$, depending on both the absolute value and energy dependence of the
cosmic ray diffusion coefficient. This suggests that only a few, or just one
nearby discrete source may explain the observed spectrum of high energy
electrons. On the other hand the measured positron fraction, after initially
increasing with particle energy, saturates at a level well below 0.5 and likely
drops above $sim 400-500$ GeV. This means that the local source(s) of TeV
electrons should not produce positrons in equal amount, ruling out scenarios
involving pulsars/pulsar winds as the main sources of high energy leptons. In
this paper we show that a single, local, and fading source can naturally
account for the entire spectrum of cosmic ray electrons in the TeV domain. Even
though the nature of such source remains unclear, we discuss known cosmic ray
accelerators, such as supernova remnant and stellar wind shocks, which are
believed to accelerate preferentially electrons rather than positrons.
The total cosmic ray electron spectrum (electrons plus positrons) exhibits a
break at a particle energy of $sim 1rm~TeV$ and extends without any
attenuation up to $rm sim 20~ TeV $. Synchrotron and inverse Compton energy
losses strongly constrain both the age and the distance of the potential
sources of TeV and multi-TeV electrons to $rmapprox 10^5~yr$ and $rm approx
100-500~pc$, depending on both the absolute value and energy dependence of the
cosmic ray diffusion coefficient. This suggests that only a few, or just one
nearby discrete source may explain the observed spectrum of high energy
electrons. On the other hand the measured positron fraction, after initially
increasing with particle energy, saturates at a level well below 0.5 and likely
drops above $sim 400-500$ GeV. This means that the local source(s) of TeV
electrons should not produce positrons in equal amount, ruling out scenarios
involving pulsars/pulsar winds as the main sources of high energy leptons. In
this paper we show that a single, local, and fading source can naturally
account for the entire spectrum of cosmic ray electrons in the TeV domain. Even
though the nature of such source remains unclear, we discuss known cosmic ray
accelerators, such as supernova remnant and stellar wind shocks, which are
believed to accelerate preferentially electrons rather than positrons.
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