arXiv Analytics

Sign in

arXiv:1804.05056 [astro-ph.HE]AbstractReferencesReviewsResources

Acceleration of X-ray Emitting Electrons in the Crab Nebula

Gwenael Giacinti, John G. Kirk

Published 2018-04-13Version 1

We study particle acceleration at the termination shock of a striped pulsar wind by integrating trajectories in a prescribed model of the magnetic field and flow pattern. Drift motion on the shock surface maintains either electrons or positrons on "Speiser" orbits in a ring-shaped region close to the equatorial plane of the pulsar, enabling them to be accelerated to very high energy by the first-order Fermi mechanism. A power-law spectrum results: $dN_{\rm e}/d\gamma\propto\gamma^{\alpha_{\rm e}}$, where $\alpha_{\rm e}$ lies in the range $-1.8$ to $-2.4$ and depends on the downstream turbulence level. For sufficiently strong turbulence, $\alpha_{\rm e} \simeq -2.2$, and both the photon index and the flux of $1-100$ keV X-rays from the Crab Nebula, as measured by NuSTAR, can be reproduced. The particle spectrum hardens to $\alpha_{\rm e} \simeq -1.8$ at lower turbulence levels, which may explain the hard photon index observed by the Chandra X-ray Observatory in the central regions of the Nebula.

Related articles: Most relevant | Search more
arXiv:1710.04493 [astro-ph.HE] (Published 2017-10-12)
Inductive spikes in the Crab Nebula - a theory of gamma-ray flares
arXiv:1701.01778 [astro-ph.HE] (Published 2017-01-06)
Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory
arXiv:1409.1112 [astro-ph.HE] (Published 2014-09-03)
Using optical lines to study particle acceleration at supernova remnants