Hydrocarbon dust absorption in Seyfert galaxies and ULIRGs

We present new spectroscopic observations of the 3.4μm absorption feature in a Seyfert 2 galaxy and a ULIRG. A signature of C–H bonds in aliphatic hydrocarbons, the 3.4μm feature indicates the presence of organic material in Galactic and extragalactic dust. The feature in these galaxies closely resembles that seen in the Galactic diffuse ISM and in newly-formed dust in a protoplanetary nebula. This similarity implies a common composition for the hydrocarbon component of interstellar dust in a range of galaxy types, and one which is resistant to processing in the interstellar and/or circumnuclear medium.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html