AAS 201st Meeting, January, 2003
Session 133. Stars, Gas, and Dust in the Universe
Invited, Thursday, January 9, 2003, 11:40am-12:30pm, 6AB

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[133.01] Stars, Gas, and Dust in the Universe

D. Calzetti (Space Telescope Science Institute)

The interplay between stars, gas, and dust determines the spectral energy distribution (SED) of non-active galaxies and, ultimately, the observable quantities at any wavelength. Such observables have a profound impact on our understanding of how galaxies evolve, as they represent our probes into the Universe. The age distribution of the stars, the intensity and distribution of the recent star formation, and the content and distribution of dust in the galaxy provide the bulk SED properties. Far from being a secondary `ingredient', dust contributes one-half or more of the energy budget in galaxies at all redshifts. I review recent progress in our knowledge of the star formation and of the dust content of galaxies in the local Universe, and of their evolution as a function of cosmic time. I discuss how global galactic parameters (morphology, luminosity, and activity level) are linked to the dust content and opacity of galaxies. Much of what we do not know about dust and star formation is related to limitations in our observational capabilities, either in the multi-wavelength range or in the angular scales probed. For instance, the physical relationship between the stellar populations and the various dust emission components in galaxies has so far remained uncharted because of the spatial resolution mismatch between optical and far-infrared telescopes. I highlight how upcoming facilities in the near future (e.g., SIRTF) can shed light on a number of such open issues.

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