XMM‐NewtonObservations of the Supernova Remnant IC 443. I. Soft X‐Ray Emission from Shocked Interstellar Medium

The shocked interstellar medium around IC443 produces strong X-ray emissionin the soft energy band (E<1.5 keV). We present an analysis of such emission asobserved with the EPIC MOS cameras on board the XMM-Newotn observatory, withthe purpose to find clear signatures of the interactions with the interstellarmedium (ISM) in the X-ray band, which may complement results obtained in otherwavelenghts. We found that the giant molecular cloud mapped in CO emission islocated in the foreground and gives an evident signature in the absorption ofX-rays. This cloud may have a torus shape and the part of torus interactingwith the IC443 shock gives rise to 2MASS-K emission in the southeast. Themeasured density of emitting X-ray shocked plasma increases toward thenortheastern limb, where the remnant is interacting with an atomic cloud. Wefound an excellent correlation between emission in the 0.3-0.5 keV band andbright optical/radio filament on large spatial scales. The partial shellstructure seen in this band therefore traces the encounter with the atomiccloud.