High resolution spectroscopy of the 11.3 micron emission band

High resolution spectra of the 11.3 micron emission band in M82 and NGC 7027 were obtained using the University of Texas IR echelle spectrometer on the IRTF in April 1988. The spectral resolution was 0.004 micron, with coverage from 11.0 to 11.6 microns. Spectra were measured at ten positions along a 10 min. long slit. Analysis of the data is still in progress, but initial results show no clear evidence of narrow structure within the feature. The analysis will involve comparison of the observed spectra to laboratory and predicted spectra of Polycylic Aromatic Hydrocarbons (PAHs) and Quenched Carbonaceous Composite (QCCs) to determine which may be responsible for the emission. The spectra will be examined with a goal of determining whether the emission is caused by molecular or solid state material. The data are also examined for evidence of variations in the shape and strength of the 11.3 micron feature with position on the sky. In NGC 7027 the 10 min. long slit went across the edge of the ionized nebulae, allowing comparison of emission from both ionized and neutral regions.