Infrared spectral energy distributions of z ∼ 0.7 star-forming galaxies

Xian Zhong Zheng, Hervé Dole, Eric F. Bell, Emeric Le Floc'h, George H. Rieke, Hans Walter Rix, David Schiminovich

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

We analyze the infrared (IR) spectral energy distributions (SEDs) for 10 μm < λrest < 100 μm for ∼600 galaxies at z ∼ 0.7 in the extended Chandra Deep Field South by stacking their Spitzer 24, 70, and 160 μm images. We place interesting constraints on the average IR SED shape in two bins: the brightest 25% of z ∼ 0.7 galaxies detected at 24 μm, and the remaining 75% of individually detected galaxies. Galaxies without individual detections at 24 μm were not well detected at 70 and 160 μm even through stacking. We find that the average IR SEDs of z ∼ 0.7 star-forming galaxies fall within the diversity of z ∼ 0 templates. While dust obscuration LIR/LUV seems to be only a function of star formation rate (SFR; ∼LIR + LUV), not of redshift, the dust temperature of star-forming galaxies (with SFR ∼ 10 M yr-1) at a given IR luminosity was lower at z ∼ 0.7 than today. We suggest an interpretation of this phenomenology in terms of dust geometry: intensely star-forming galaxies at z ∼ 0 are typically interacting, and host dense centrally concentrated bursts of star formation and warm dust temperatures. At z ∼ 0.7, the bulk of intensely star-forming galaxies are relatively undisturbed spirals and irregulars, and we postulate that they have large amounts of widespread lower density star formation, yielding lower dust temperatures for a given IR luminosity. We recommend which IR SEDs are most suitable for modeling intermediate-redshift galaxies with different SFRs.

Original languageEnglish (US)
Pages (from-to)301-312
Number of pages12
JournalAstrophysical Journal
Volume670
Issue number1
DOIs
StatePublished - Nov 20 2007

Keywords

  • Galaxies: evolution
  • Galaxies: starburst
  • Infrared: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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