Abstract
We review recent Infrared Space Observatory (ISO) and near-infrared observations of a number of supernova remnants, which are interacting with molecular clouds. Atomic fine-structure lines of [C II], [N II], [N III, [O I], [O II], [O III], [Si II], [P II], [Fe II], and two lines of shocked molecular hydrogen S(3) and S(9), were detected for three remnants using ISO. Virtually all existing atomic lines are detected. No single shock model can account for all of the observed lines, and to explain the detected lines requires both moderate ( 10^2cm-3) and high ( ~ 10^4cm-3) pre-shock densities. The inferred high density and warm temperatures are from heated dense clumps due to supernova shocks, and the principal coolants of radiative shocks are [O I] 63 µ and [Si II] 34.8 µ lines. Shock-excited far-infrared emission of H[2]O, OH, and CO is also detected, which is consistent with collisional excitation in warm, very dense ( 2×10^5cm-3) gas. We also took high-resolution images of molecular hydrogen and [Fe II] using ground-based observations, which reveal how shocks develop around clouds. Displacements between molecular hydrogen and [Fe II] structures are often observed, and the images show that a single primary shock is present on large scales. The possibility of star formation induced by supernova shocks when SN shocks interact with clouds is discussed.
