Soft X-ray profile and spectrum of the supernova remnant IC 443

Abstract

The spectrum and emission profile of IC 443 are presented in the 0.5 to 3 keV band. The data are fitted by power-law and bremsstrahlung emission models with interstellar absorption. A characteristic temperature of 10(+18, -4) -10/sup 6/ K with a hydrogen column density of 3.5(+2, -1.7) -10/sup 21/ atoms cm/sup -2/ is obtained. The emission profile is presented for a scan along the northwest-southwest axis with 9' resolution. The X-ray emission is centered at ..cap alpha.. (1950) =6/sup h/13/sup m/45/sup s/ +- 15/sup s/, delta=22degree29' +- 4', with the strongest emission found in the northern part of the remnant. The results indicate a gross correlation with the enhanced radio and optical activity in the northeastern segment. Interpretation within the standard shock-wave model yields an age of 4000(+2500, -1800) years, in conflict with some other determinations. A possible reconciliation exists if the X-ray emission arises primarily in shocked intercloud medium, as suggested by McKee and Cowie, and the optical and radio emission arises primarily in shocked clouds. In this scenario the pulsar PSR 0611+22 may not be associated with the remnant. The constraints on the soft X-ray absorption to the remnants are used to set a lower limit of 1more » kpc for the distance to the remnant. (AIP)« less