The dust attenuation of star-forming galaxies at z ∼ 3 and beyond: New insights from ALMA observations

Y. Fudamoto, P. A. Oesch, E. Schinnerer, B. Groves, A. Karim, B. Magnelli, M. T. Sargent, P. Cassata, P. Lang, D. Liu, O. Le Fèvre, S. Leslie, V. Smolčić, L. Tasca

Research output: Contribution to journalArticlepeer-review


We present results on the dust attenuation of galaxies at redshift ∼ 3 − 6 by studying the relationship between the UV spectral slope (βUV) and the infrared excess (IRX; LIR/LUV) using ALMA far-infrared continuum observations. Our study is based on a sample of 67 massive, star-forming galaxies with a median mass of M∼ 1010.7 M☉ spanning a redshift range z = 2.6−3.7 (median z = 3.2) that were observed with ALMA at λrest = 300 µm. Both the individual ALMA detections (41 sources) and stacks including all galaxies show the IRX–βUV relationship at z ∼ 3 is mostly consistent with that of local starburst galaxies on average. However, we find evidence for a large dispersion around the mean relationship by up to ±0.5 dex. Nevertheless, the locally calibrated dust correction factors based on the IRX–βUV relation are on average applicable to main-sequence z ∼ 3 galaxies. This does not appear to be the case at even higher redshifts, however. Using public ALMA observations of z ∼ 4 − 6 galaxies we find evidence for a significant evolution in the IRX–βUV and the IRX–M relations beyond z ∼ 3 toward lower IRX values. We discuss several caveats that could affect these results, including the assumed dust temperature. ALMA observations of larger z > 3 galaxy samples will be required to confirm this intriguing redshift evolution.

Original languageEnglish
JournalUnknown Journal
Publication statusPublished - 2017 May 3
Externally publishedYes


  • Galaxies: evolution
  • Galaxies: ISM
  • Galaxies: star formation
  • Submillimetre: ISM

ASJC Scopus subject areas

  • General

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