We are indebted to François Boulanger for having shared with us prior to publication, his ideas on the profiles of PAH features. We thanks Mario van den Ancker and Malcolm Walmsley for interesting comments to this paper. This work was supported in part by CNR grant 97.00018.CT02 and ASI grant ARS-66-96 to the Osservatorio di Arcetri.
© European Southern Observatory (ESO) 1998
Online publication: September 30, 1998