Issue |
A&A
Volume 368, Number 3, March IV 2001
|
|
---|---|---|
Page(s) | 1063 - 1070 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361:20010021 | |
Published online | 15 March 2001 |
Cosmic-ray positrons from mature gamma-ray pulsars
1
Department of Physics, Yunnan University, Kunming, China
2
Department of Physics, University of Hong Kong, Hong Kong, China
Corresponding author: L. Zhang, lzhang@bohr.physics.hku.hk
Received:
12
May
2000
Accepted:
19
December
2000
We consider a possible contribution of mature γ-ray pulsars (with
ages of yrs) to cosmic ray positrons. Within the framework of
the γ-ray pulsar outer gap model,
pairs in the pulsar
magnetosphere are produced by the cascade of
pairs through
synchrotron radiation of the return current from the outer gap. A
good fraction of these cascade
pairs are reflected by the
hard X-rays from the polar cap via resonant scattering and escape
from the pulsar through the light cylinder. The escaped pairs are
accelerated to relativistic energies in the pulsar wind driven by
low-frequency electromagnetic waves. Using Monte Carlo simulations, we
generate a sample of the mature γ-ray pulsars in our Galaxy and
calculate the positron production rate from these pulsars. In a simple
"leaky box" model, we calculate the ratio of cosmic-ray positrons to total
electrons. Our result indicates that the pulsar contribution to the
cosmic ray positrons peaks at about 60 GeV and the observed
ratio can be explained in this model.
Key words: stars: pulsars: general / acceleration of particles / ISM: cosmic rays
© ESO, 2001
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