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

Safarzadeh, Mohammadtaher and Hayward, Christopher C. and Ferguson, Henry C. and Somerville, Rachel S. (2016) What shapes the far-infrared spectral energy distributions of galaxies? Astrophysical Journal, 818 (1). Art. No. 62. ISSN 0004-637X.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hayward, Christopher C.0000-0003-4073-3236
Ferguson, Henry C.0000-0001-7113-2738
Additional Information:© 2016. The American Astronomical Society. Received 2015 August 31; accepted 2015 December 22; published 2016 February 8. We thank Maarten Baes for comments on the manuscript and Brice Menard and Nick Scoville for useful discussions. C.C.H. is grateful to the Gordon and Betty Moore Foundation for financial support. C.C.H. and R.S.S. acknowledge the hospitality of the Aspen Center for Physics, which is supported by the National Science Foundation Grant No. PHY-1066293. R.S.S. is grateful to the Downsbrough family for their support and acknowledges support from the Simons Foundation in the form of a Simons Investigator Award. This work was partially supported by NASA's Astrophysics Data Analysis Program, under grant NNX15AE54G.
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Downsbrough familyUNSPECIFIED
Simons FoundationUNSPECIFIED
Subject Keywords:dust, extinction
Issue or Number:1
Record Number:CaltechAUTHORS:20150924-140513546
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Official Citation:Mohammadtaher Safarzadeh et al 2016 ApJ 818 62
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60487
Deposited By: Christopher Hayward
Deposited On:24 Sep 2015 23:03
Last Modified:14 Dec 2019 05:57

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