Spectral Energy Distributions of Local Luminous and Ultraluminous Infrared Galaxies

November 2012 • 2012ApJS..203....9U

Authors • U, Vivian • Sanders, D. B. • Mazzarella, J. M. • Evans, A. S. • Howell, J. H. • Surace, J. A. • Armus, L. • Iwasawa, K. • Kim, D. -C. • Casey, C. M. • Vavilkin, T. • Dufault, M. • Larson, K. L. • Barnes, J. E. • Chan, B. H. P. • Frayer, D. T. • Haan, S. • Inami, H. • Ishida, C. M. • Kartaltepe, J. S. • Melbourne, J. L. • Petric, A. O.

Abstract • 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 (\bar{R}_{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, (\bar{R}_1.4\,GHz = -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^-1) and from the monochromatic UV luminosities (SFR_UV ~ 1.3 M _⊙ yr^-1), 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.

Links

• PREPRINT http://arxiv.org/abs/1209.1611
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2012ApJS..203....9U
• ELECTR https://doi.org/10.1088%2F0067-0049%2F203%2F1%2F9
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2012ApJS..203....9U
• PDF https://iopscience.iop.org/article/10.1088/0067-0049/203/1/9/pdf
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• DATA https://hst.esac.esa.int/ehst/#/pages/search;bibcode=2012ApJS..203....9U
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• SPIRES http://inspirehep.net/search?p=find+eprint+arXiv:1209.1611