Spatial distribution of Unidentified Infrared emission Bands in star forming regions

Abstract

Midcourse Space Experiment (MSX) has surveyed the Galactic plane in four infrared bands between 6 and 25 /Lm, two of which cover several Unidentified Infrared emission Bands (UIBs). A scheme has been developed to extract the spatial distribution of the UIB emission using the MSX data. The observations have been modelled by two components: (i) the emission in urns and (ii) an underlying thermal continuum (gray body) from the interstellar dust. The reliability of the scheme has been successfully verified by comparing the results for a sample of five Galactic compact H II regions (Sh-61, Sh-138, Sh-152, Sh-156, Sh-186) for which ISOCAM images in some individual UIBs are available. Our scheme demonstrates the usefulness of the MSX database for study of large scale spatial distribution of VIB emission (and the carriers of UIBs) in the entire Galactic plane.