Dr. J.D. Smith
Univeristy of Arizona

University of Florida Astronomy Colloquium - Nov. 15th, 2006

The SINGS Spitzer Legacy: Seeing Nearby Galaxies in a New Light

The Spitzer Space Telescope is revolutionizing our understanding of star formation and the dusty interstellar media of galaxies. The unprecedented resolution and sensitivity of the Spitzer images, when combined with observations at ultraviolet, visible, and radio wavelengths, are providing for the first time complete, detailed maps of the current star formation covering the full range of interstellar environments and evolutionary stages. The same data delineate the structure and topology of the cold ISM in galaxies with unprecedented depth and detail. The Spitzer mid-infrared spectra provide information on the physical conditions in all phases of gas, from the ionized regions surrounding massive stars to the surrounding PDR, neutral, molecular, and shocked environments.

This talk will highlight results from the Spitzer Infrared Nearby Galaxies Survey (SINGS), a comprehensive, multi-wavelength Legacy survey of 75 nearby galaxies that span the full range of types, luminosities, and infrared properties found in the local universe, with a special emphasis on the power of spatially resolved spectroscopy to probe the variable mid-infrared emission spectrum of star-forming galaxies, and the surprising role low-luminosity AGN are playing in modifying the fundamental mid-infrared star-formation tracer -- the PAH molecular emission bands.