Issue |
A&A
Volume 410, Number 1, October IV 2003
|
|
---|---|---|
Page(s) | 189 - 198 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20031274 | |
Published online | 17 November 2003 |
Cosmic ray production in supernova remnants including reacceleration: The secondary to primary ratio
1
Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677891 Yakutsk, Russia e-mail: berezhko@ikfia.ysn.ru
2
Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan e-mail: ksenofon@icrr.u-tokyo.ac.jp
3
Institute for Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Troitsk, Moscow region 142092, Russia e-mail: vptuskin@izmiran.rssi.ru; zirak@izmiran.rssi.ru
4
Max-Planck-Institut für Kernphysik, Postfach 103980, 69029 Heidelberg, Germany
Corresponding author: H. J. Völk, heinrich.voelk@mpi-hd.mpg.de
Received:
16
April
2003
Accepted:
29
July
2003
We study the production of cosmic rays (CRs) in supernova
remnants (SNRs), including the reacceleration of background galactic
cosmic rays (GCRs) – thus refining the early considerations by
Blandford
& Ostriker (1980) and Wandel et al. (1987) – and the effects of the
nuclear spallation inside the sources (the SNRs). This combines for the
first time nuclear spallation inside CR sources and in the diffuse
interstellar medium, as well as reacceleration, with the injection and
subsequent acceleration of suprathermal particles from the postshock
thermal pool. Selfconsistent CR spectra are calculated on the basis of the
nonlinear kinetic model. It is shown that GCR reacceleration and CR
spallation produce a measurable effect at high energies, especially in the
secondary to primary (s/p) ratio, making its energy-dependence
substantially flatter than predicted by the standard model.
Quantitatively, the effect depends strongly upon the density of the
surrounding circumstellar matter. GCR reacceleration dominates secondary
CR production for a low circumstellar density. It increases the expected
s/p ratio substantially and flattens its spectrum to an almost
energy-independent form for energies larger than 100 GeV/n if the
supernovae explode on average into a hot dilute medium with hydrogen
number density cm-3. The contribution of CR
spallation inside SNRs to the s/p ratio increases with increasing
circumstellar density and becomes dominant for
cm-3, leading at high energies to a flat s/p ratio which is only
by a factor of three lower than in the case of the hot medium.
Measurements of the boron to carbon ratio at energies above 100 GeV/n
could be used in comparison with the values predicted here as a
consistency test for the supernova origin of the GCRs.
Key words: ISM: cosmic rays / shock waves / stars: supernovae: general
© ESO, 2003
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