On the dust temperatures of high-redshift galaxies

Lichen Liang*, Robert Feldmann, Dušan Kereš, Nick Z. Scoville, Christopher C. Hayward, Claude André Faucher-Giguère, Corentin Schreiber, Xiangcheng Ma, Philip F. Hopkins, Eliot Quataert

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

101 Scopus citations


Dust temperature is an important property of the interstellar medium (ISM) of galaxies. It is required when converting (sub)millimetre broad-band flux to total infrared luminosity (LIR), and hence star formation rate, in high-redshift galaxies. However, different definitions of dust temperatures have been used in the literature, leading to different physical interpretations of how ISM conditions change with, e.g. redshift and star formation rate. In this paper, we analyse the dust temperatures of massive (Mstar > 1010 M) z = 2-6 galaxies with the help of high-resolution cosmological simulations from the Feedback in Realistic Environments (FIRE) project. At z ∼ 2, our simulations successfully predict dust temperatures in good agreement with observations. We find that dust temperatures based on the peak emission wavelength increase with redshift, in line with the higher star formation activity at higher redshift, and are strongly correlated with the specific star formation rate. In contrast, the mass-weighted dust temperature, which is required to accurately estimate the total dust mass, does not strongly evolve with redshift over z = 2-6 at fixed IR luminosity but is tightly correlated with LIR at fixed z. We also analyse an 'equivalent' dust temperature for converting (sub)millimetre flux density to total IR luminosity, and provide a fitting formula as a function of redshift and dust-to-metal ratio. We find that galaxies of higher equivalent (or higher peak) dust temperature ('warmer dust') do not necessarily have higher mass-weighted temperatures. A 'two-phase' picture for interstellar dust can explain the different scaling relations of the various dust temperatures.

Original languageEnglish (US)
Pages (from-to)1397-1422
Number of pages26
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Oct 11 2019


  • Galaxies: ISM
  • Galaxies: evolution
  • Galaxies: high-redshift
  • Submillimetre: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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