[Previous] | [Session 42] | [Next]
K. E. Kraemer (NRC/AFRL), G. C. Sloan (Boston College), S. D. Price (AFRL)
Two of the most important features in the mid-infrared spectra of star-forming regions are the unidentified infrared (UIR) emission bands at 3.3, 6.2, 7.8, 8.6, and 11.2 microns and the broad silicate absorption feature centered around 9.7 microns. Conventional wisdom holds that emission from the UIR bands and the silicate absorption feature do not arise from the same dust. However, in a sufficiently large telescope beam, both the emission bands and the absorption feature may be detected in the same source. To investigate how often this might occur, we have examined the ISO (Infrared Space Observatory) archive of SWS (Short Wavelength Spectrometer) spectra. We find that a significant fraction of the non-stellar sources observed show both emission and absorption features in their SWS spectra. Procedures for disentangling the emission and absorption features from each other, as well as from the underlying continuum and from additional features, such as fine-structure emission lines and ice absorption bands, are discussed. The possibility that the two features could, in fact, arise from the same material is also discussed.