SPECTRAL ENERGY DISTRIBUTIONS OF LOCAL LUMINOUS AND ULTRALUMINOUS INFRARED GALAXIES
- Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
- Infrared Processing and Analysis Center, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States)
- Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States)
- Spitzer Science Center, 1200 E. California Blvd., MS 314-6, California Institute of Technology, Pasadena, CA 91125 (United States)
- ICREA and Institut del Ciencies del Cosmos, Universitat de Barcelona (IEEC-UB), Marti i Franques, 1, E-08028 Barcelona (Spain)
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)
- Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06511 (United States)
- National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States)
- CSIRO Astronomy and Space Science, Marsfield NSW, 2122 (Australia)
Luminous (LIRGs; log (L{sub IR}/L{sub Sun }) = 11.00-11.99) and ultraluminous infrared galaxies (ULIRGs; log (L{sub IR}/L{sub Sun }) = 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{sub IR}/L{sub Sun }) = 11.14-12.57 from the flux-limited (f{sub 60{mu}m} > 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 ({approx}0.3-2 {mu}m), and a dominant FIR ({approx}40-200 {mu}m) thermal dust peak, where {nu}L{sub {nu}}(60 {mu}m)/{nu}L{sub {nu}}(V) increases from {approx}2 to 30 with increasing L{sub IR}. When normalized at IRAS 60 {mu}m, the largest range in the luminosity ratio, R({lambda}) {identical_to} log[{nu}L{sub {nu}}({lambda})/{nu}L{sub {nu}}(60 {mu}m)], observed over the full sample is seen in the hard X-rays (HX = 2-10 keV), where {Delta}R{sub HX} = 3.73 (R-bar{sub HX}= -3.10). A small range is found in the radio (1.4 GHz), {Delta}R{sub 1.4GHz} = 1.75, where the mean ratio is largest, (R-bar{sub 1.4GHz}= -5.81). Total infrared luminosities, L{sub IR}(8-1000 {mu}m), 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 {approx}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{sub *}/M{sub Sun }) = 10.79 {+-} 0.40. Star formation rates have been determined from the infrared (SFR{sub IR} {approx} 45 M{sub Sun} yr{sup -1}) and from the monochromatic UV luminosities (SFR{sub UV} {approx} 1.3 M{sub Sun} yr{sup -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.
- OSTI ID:
- 22089800
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 203, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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