Dust in the Magellanic Clouds

Abstract

AbstractThe Magellanic Clouds are important templates for studying the role interstellar dust plays as actor and tracer of galaxy evolution. Due to their proximity, the Large and Small Magellanic clouds are uniquely suited to put detailed Galactic dust studies in a global context. With a metal abundance lower than that of the Sun, the Magellanic Clouds also permit to characterize interstellar matter composition and structure as a function of metallicity. The presentation of spectacular results from the AKARI and Spitzer surveys was one of the highlights of this Magellanic Clouds meeting. This paper puts these results in context. I discuss UV extinction and IR emission signatures of carbon and silicate dust. I present diverse evidence of dust processing in the ISM. I illustrate the correlation between the mm emission of dust, and gas column density using Milky Way surveys. I conclude with three main results. Dust in the SMC is not carbon poor. The composition of interstellar dust reflects its processing in interstellar space and thereby depends on local conditions and its past history. In the Magellanic Clouds, far-IR and sub-mm observations are indicating that there may be significantly more cold interstellar matter, cold H i and H2 gas, than estimated from H i and CO observations.