Infrared Spectroscopy of Supernova Remnants

Spectra of several galactic and LMC supernova remnants have been obtained at R ~ 1500 in the 1−2.5 µm region with the cooled grating/array spectrometer, IRSPEC, on the ESO 3.6m telescope. The brightest lines observed are from [FeII]. In RCW 103, which exhibits the highest surface brightness, H (Brγ at 2.17µm) and H 2 (1−0 S(1) at 2.12µm) lines have also been detected. A good correlation is found between [FeII] (1.64µm) and Hβ implying similar ionization structures and Fe abundances in a wide variety of remnants. The actual [FeII](1.64µm)/Hβ ratio of ~0.2 also implies a high depletion factor (>0.9) for Fe. Electron densities, extinctions and [FeII] luminosities derived from these data are presented and discussed and attention drawn to a potentially interesting discrepancy between H(Brγ) and Hβ fluxes.