Submillimetre flux as a probe of molecular ISM mass in high-z galaxies

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

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Recent long-wavelength observations on the thermal dust continuum suggest that the Rayleigh-Jeans tail can be used as a time-efficient quantitative probe of the dust and interstellar medium (ISM) mass in high-z galaxies. We use high-resolution cosmological simulations from the Feedback in Realistic Environment (FIRE) project to analyse the dust emission of M∗ 1010 M galaxies at z= 2-4. Our simulations (MassiveFIRE) explicitly include various forms of stellar feedback, and they produce the stellar masses and star formation rates of high-z galaxies in agreement with observations. Using radiative transfer modelling, we show that sub-millimetre (sub-mm) luminosity and molecular ISM mass are tightly correlated and that the overall normalization is in quantitative agreement with observations. Notably, sub-mm luminosity traces molecular ISM mass even during starburst episodes as dust mass and mass-weighted temperature evolve only moderately between z = 4 and z = 2, including during starbursts. Our finding supports the empirical approach of using broadband sub-mm flux as a proxy for molecular gas content in high-z galaxies. We thus expect single-band sub-mm observations with ALMA to dramatically increase the sample size of high-z galaxies with reliable ISM masses in the near future.

Original languageEnglish (US)
Pages (from-to)L83-L88
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
StatePublished - Jul 1 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • galaxies: ISM
  • galaxies: evolution
  • galaxies: high-redshift
  • submillimetre: galaxies


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