What shapes the far-infrared spectral energy distributions of galaxies?

Journal Article · Wed Feb 10 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/818/1/62· OSTI ID:22887049

Safarzadeh, Mohammadtaher ^[1]; Hayward, Christopher C. ^[2]; Ferguson, Henry C. ^[3]

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1. Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States)
2. TAPIR 350-17, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States)
3. Space Telescope Science Institute, 3700 San Martin Boulevard, Baltimore, MD 21218 (United States)

To explore the connection between the global physical properties of galaxies and their far-infrared (FIR) spectral energy distributions (SEDs), we study the variation in the FIR SEDs of a set of 51 hydrodynamically simulated galaxies, both mergers and isolated systems representative of low- and high-redshift galaxies, that are generated by performing dust radiative transfer in post-processing. We study the FIR SEDs using principal component (PC) analysis, and find that 97% of the variance in the sample can be explained by two PCs. The first PC characterizes the wavelength of the peak of the FIR SED, and the second encodes the breadth of the SED. We find that the coefficients of both PCs can be predicted well using a double power law in terms of the IR luminosity and dust mass, which suggests that these two physical properties are the primary determinants of galaxies’ FIR SED shapes. Incorporating galaxy sizes does not significantly improve our ability to predict the FIR SEDs. Our results suggest that the observed redshift evolution in the effective dust temperature at a fixed IR luminosity is not driven by geometry: the SEDs of z∼2−3 ultraluminous IR galaxies (ULIRGs) are cooler than those of local ULIRGs, not because the high-redshift galaxies are more extended, but rather because they have higher dust masses at fixed IR luminosity. Finally, based on our simulations, we introduce a two-parameter set of SED templates that depend on both IR luminosity and dust mass.

• OSTI ID: 22887049
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 818; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPUTERIZED SIMULATION
COSMIC DUST
ENERGY SPECTRA
FAR INFRARED RADIATION
GALAXIES
LUMINOSITY
MASS
RADIANT HEAT TRANSFER
RED SHIFT