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Paper: Spitzer Space Telescope and the Physics of Interstellar Matter
Volume: 357, The Spitzer Space Telescope: New Views of the Cosmos
Page: 305
Authors: Draine, B.T.
Abstract: This article focuses on some highlights from this meeting which illustrate how Spitzer Space Telescope is providing new insights into the physics of interstellar matter. Spectroscopy with Spitzer is revealing new aspects of the emission features attributed to PAHs – new spectral properties, and spectral variations from position to position, and from galaxy to galaxy – providing valuable constraints that will guide us toward a better understanding the physical properties of the emitters, and their abundances. The angular power spectrum of the diffuse emission from interstellar clouds may tell us about both MHD turbulence and the physics of the PAHs emitting in the 8μm band. The 4.5μm band of the IRAC camera appears to be a good tracer of fast outflows in molecular clouds; the emitter is not certain, but appears likely to be H2 in (v, J) = (0, 11), (0,12), and (0,13). Spitzer is able to study the IR-radio correlation as a function of position within spiral galaxies, and is finding variations of up to a factor of 10 in the IR/radio ratio from point to point. The sensitivity of Spitzer's spectrograph enables studies of ices in molecular clouds on “typical” sightlines, not just those towards unusually luminous infrared sources. We can also anticipate progress on the mineralogy of circumstellar and interstellar dust.
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