Constraints on the diffusive shock acceleration from the nonthermal X-ray thin shells in SN 1006 NE rim

¹ Department of Physics, Kyoto University, Kyoto 606-8502, Japan e-mail: yamazaki@tap.scphys.kyoto-u.ac.jp,bamba@cr.scphys.kyoto-u.ac.jp, koyama@cr.scphys.kyoto-u.ac.jp
² Faculty of Science, Ibaraki University, Mito 310-8512, Japan e-mail: yoshidat@mx.ibaraki.ac.jp
³ Earth & Planetary Science, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113 Tokyo, Japan e-mail: terasawa@eps.s.u-tokyo.ac.jp

Corresponding author: R. Yamazaki, yamazaki@tap.scphys.kyoto-u.ac.jp

Received: 20 August 2003
Accepted: 6 November 2003

Abstract

Characteristic scale lengths of nonthermal X-rays from the SN 1006 NE rim, which are observed by Chandra, are interpreted in the context of diffusive shock acceleration with the assumption that the observed spatial profile of nonthermal X-rays corresponds to that of accelerated electrons with energies of a few tens of TeV. To explain the observed scale lengths, we construct two simple models with a test particle approximation, where the maximum energy of accelerated electrons is determined by the age of SN 1006 (age-limited model) or the energy loss (energy loss-limited model), and constrain the magnetic field configuration and the diffusion coefficients of accelerated electrons. When the magnetic field is nearly parallel to the shock normal, the magnetic field should be in the range of 20–85  and highly turbulent both upstream and downstream, which means that the mean free path of accelerated electrons is of the order of their gyro-radius (Bohm limit). This situation can be realized both in the age-limited and energy loss-limited model. On the other hand, when the magnetic field is nearly perpendicular to the shock normal, which can exist only in the age-limited case, the magnetic field is several  upstream and 14–20  downstream, and the upstream magnetic field is less turbulent than the downstream.