Sabrina Stierwalt (SSC/Caltech) : Cold Gas and Warm Dust in Luminous Infrared Galaxies

Nearby Luminous Infrared Galaxies (LIRGs) act as local analogs of the extreme star forming environments that dominate star formation at z~1 and thus play a central role in our understanding of galaxy evolution. I will present the mid- IR properties for the Great Observatories All-Sky LIRG Survey (GOALS) sample of 182 nearby LIRGs and 20 ULIRGs as derived from a multi-component spectral decomposition of low resolution spectroscopy from Spitzer IRS. The results derived from our detailed fitting technique are combined with data from other wavelengths to explore the cause of the differences in the dust characteristics (ionization state, grain size) for dusty versus unobscured LIRGs. I also trace the relative PAH emission and dust obscuration throughout the merging process. Finally, I will also present the first results of a multiwavelength study to take a census of global measurements of cold dust, molecular gas, and neutral hydrogen in the GOALS (U)LIRGs.