New evidence for strong nonthermal effects in Tycho's supernova remnant.

For the case of Tycho's supernova remnant (SNR) we present the relation between the blast wave and contact discontinuity radii calculated within the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is demonstrated that these radii are confirmed by recently published Chandra measurements which show that the observed contact discontinuity radius is so close to the shock radius that it can only be explained by efficient CR acceleration which in turn makes the medium more compressible. Together with the recently determined new value Esn=1.2×1051 erg of the SN explosion energy this also confirms our previous conclusion that a TeV γ-ray flux of (2-5)×10−13 erg/(cm2 s) is to be expected from Tycho's SNR. Chandra measurements and the HEGRA upper limit of the TeV γ-ray flux together limit the source distance d to 3.3≤d≤4 kpc. [ABSTRACT FROM AUTHOR]