Expected gamma-ray emission of supernova remnant SN 1987a

Abstract

A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants (SNRs) is employed to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-100yr. It is shown that an efficient production of nuclear CRs leads to a strong modification of the outer SNR shock and to a large downstream magnetic field Bd ≈ 20 mG. The shock modification and the strong field are required to yield the steep radio emission spectrum observed, as well as the considerable synchrotron cooling of high-energy electrons which diminishes their X-ray synchrotron flux. These features are also consistent with the existing X-ray observations. The expected γ-ray energy flux atTeV energies at the current epoch is nearly εγ Fγ ≈ 4 × 10 -13ergcm2 s-1 under reasonable assumptions about the overall magnetic field topology and the turbulent perturbations of this field. The general nonthermal strength of the source is expected to increase roughly by a factor of two over the next 15-20years; thereafter, it should decrease with time in a secular form. © 2011. The American Astronomical Society. All rights reserved.