ISOCAM spectro-imaging of the H_2 rotational lines hfill in the supernova remnant IC 443

Abstract

We report spectro-imaging observations of the bright western ridge of the supernova remnant IC {443 obtained with the ISOCAM circular variable filter (CVF) on board the Infrared Space Observatory (ISO). This ridge corresponds to a location where the interaction between the blast wave of the supernova and ambient molecular gas is amongst the strongest. The CVF data show that the 5 to 14 mu m spectrum is dominated by the pure rotational lines of molecular hydrogen (v = 0-0, S(2) to S(8) transitions). At all positions along the ridge, the H_2 rotational lines are very strong with typical line fluxes of 10(-4} to 10({-3)) erg s(-1) cm(-2) sr(-1). We compare the data to a new time-dependent shock model; the rotational line fluxes in IC {443 are reproduced within factors of 2 for evolutionary times between 1,000 and 2,000 years with a shock velocity of sim 30 km s(-1) and a pre-shock density of sim 10(4 cm(-3)) . Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.