2012ApJS..203....9U

Luminous (LIRGs; log (L_IR/L_☉) = 11.00-11.99) and ultraluminous infrared galaxies (ULIRGs; log (L_IR/L_☉) = 12.00-12.99) are the most extreme star-forming galaxies in the universe. The local (U)LIRGs provide a unique opportunity to study their multi-wavelength properties in detail for comparison with their more numerous counterparts at high redshifts. We present common large aperture photometry at radio through X-ray wavelengths and spectral energy distributions (SEDs) for a sample of 53 nearby (z < 0.083) LIRGs and 11 ULIRGs spanning log (L_IR/L_☉) = 11.14-12.57 from the flux-limited (f_60 µm_> 5.24 Jy) Great Observatories All-sky LIRG Survey. The SEDs for all objects are similar in that they show a broad, thermal stellar peak (∼0.3-2 µm), and a dominant FIR (∼40-200 µm) thermal dust peak, where νL_ν(60 µm)/νL_ν(V) increases from ∼2 to 30 with increasing L_IR. When normalized at IRAS 60 µm, the largest range in the luminosity ratio, R(λ) ≡ log[νL_ν(λ)/νL _ν(60 µm)], observed over the full sample is seen in the hard X-rays (HX = 2-10 keV), where ΔR_HX= 3.73 (_HX = -3.10). A small range is found in the radio (1.4 GHz), ΔR_1.4 GHz_= 1.75, where the mean ratio is largest, ((_1.4GHz = -5.81). Total infrared luminosities, L_IR(8-1000 µm), dust temperatures, and dust masses were computed from fitting thermal dust emission modified blackbodies to the mid-infrared (MIR) through submillimeter SEDs. The new results reflect an overall ∼0.02 dex lower luminosity than the original IRAS values. Total stellar masses were computed by fitting stellar population synthesis models to the observed near-infrared (NIR) through ultraviolet (UV) SEDs. Mean stellar masses are found to be log (M_{sstarf}/M_☉) = 10.79±0.40. Star formation rates have been determined from the infrared (SFR_IR∼ 45 M_☉/yr) and from the monochromatic UV luminosities (SFR_UV∼ 1.3 M_☉/yr), respectively. Multi-wavelength active galactic nucleus (AGN) indicators have be used to select putative AGNs: About 60% of the ULIRGs would have been classified as an AGN by at least one of the selection criteria.