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Session 40 - Supernova Remnants & SN 1987A.
Display session, Thursday, January 08
Exhibit Hall,

[40.05] Nonthermal X-rays and Gamma Rays from Supernova Remnants in Stellar-Wind Bubbles

S. P. Reynolds (NC State U.)

Electrons are expected to be accelerated in strong shock waves to energies limited by radiative losses, by the finite age of the shock, or by escape. Young supernova remnants can easily produce electron distributions that, while steepening from the slope at radio energies, still contain significant numbers of electrons at energies of 100 TeV or higher, where they produce synchrotron X-rays to 10 keV and above. In addition, these electrons can inverse-Compton scatter cosmic microwave background photons up to energies in excess of 100 GeV. For remnants of core-collapse supernovae expanding into stellar-wind bubbles, the upstream density is likely to drop as r^-2 while the upstream magnetic field is wrapped into a tight spiral, resulting in an almost perpendicular shock everywhere. Such shocks can be extremely effective in accelerating electrons to high energies. I describe spectra and images for spherical remnants, assuming the dynamics are given by the Sedov self-similar solution appropriate for an ambient r^-2 density profile (r_sh \propto t^2/3). Both images and spectra differ significantly from those for remnants expanding into uniform magnetic fields, and should be distinguishable. Remnants expanding into spherical wind bubbles should show little azimuthal variation in synchrotron brightness for any viewing angle. Except at the highest photon energies, their brightness profiles peak somewhat inside the outermost edge of emission. X-ray halos caused by electrons diffusing ahead of the shock are generally narrow and faint. I shall describe inverse-Compton gamma-ray spectra produced by these electron distributions as well.

Program listing for Thursday