X-ray evidence for the association of G11.2-0.3 with the supernova of 386 AD.

We present ROSAT observations of the radio-bright supernova remnant G1 1.2-0.3 which support the hypothesis that it is the remnant of the historical supernova SN 386 AD. The PSPC data imply a post-shock temperature of kT= 2.4 (+2.3, -1.0) keV (95 per cent confidence limits), equivalent to a shock speed of 1400 km s - , and an absorbing column density NH = 1.3 (+0.4, -0.2)x 1022 , for a homogeneous, equilibrium plasma model. For an assumed age of 1607 yr, these data imply a distance of 9 kpc and a peak apparent magnitude of about 2 mag, consistent with a Type Ia supernova. Key words: supernovae: individual: SN 386 AD - supernova remnants - X-rays: ISM.