  In the SD scenario of SNe Ia the companion survives the SN explosion and thus
should be visible near the center of the SN remnant and may show some unusual
features. A promising approach to test progenitor models of SNe Ia is to search
for the companion in SNRs. Here we present the results of 3D hydrodynamics
simulations of the interaction between the SN Ia blast wave and a MS companion
taking into consideration its orbital motion and spin. The primary goal of this
work is to investigate the rotation of surviving companions after SN Ia
explosions in the WD+MS scenario. We use Eggleton's code including the
optically thick accretion wind model to obtain realistic models of companions.
The impact of the SN blast wave on these companions is followed in 3D
hydrodynamic simulations employing the SPH code GADGET3. We find that the
rotation of the companion does not significantly affect the amount of stripped
mass and the kick velocity caused by the SN impact. However, in our
simulations, the rotational velocity of the companion is significantly reduced
to about 14% to 32% of its pre-explosion value due to the expansion of the
companion and the fact that 55%-89% of the initial angular momentum is carried
away by the stripped matter. Compared with the observed rotational velocity of
the presumed companion star of Tycho's SN, Tycho G, of 6 km/s the final
rotational velocity we obtain is still higher by at least a factor of two.
Whether this difference is significant, and may cast doubts on the suggestion
that Tycho G is the companion of SN 1572, has to be investigated in future
studies. Based on binary population synthesis results we present, for the first
time, the expected distribution of rotational velocities of companions after
the explosion which may provide useful information for the identification of
the surviving companion in observational searches in other historical SNRs.
