%AFudamoto, Yoshinobu [Department of Astronomy, University of Geneva, 51 Ch. des Maillettes, 1290 Versoix, Switzerland]%AFudamoto, Yoshinobu [Department of Astronomy, University of Geneva, 51 Ch. des Maillettes, 1290 Versoix, Switzerland]%AOesch, P. [Department of Astronomy, University of Geneva, 51 Ch. des Maillettes, 1290 Versoix, Switzerland, International Associate, Cosmic Dawn Center (DAWN), 2100 Copenhagen, Denmark]%AOesch, P. [Department of Astronomy, University of Geneva, 51 Ch. des Maillettes, 1290 Versoix, Switzerland, International Associate, Cosmic Dawn Center (DAWN), 2100 Copenhagen, Denmark]%AMagnelli, B. [Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany]%AMagnelli, B. [Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany]%ASchinnerer, E. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%ASchinnerer, E. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%ALiu, D. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%ALiu, D. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%ALang, P. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%ALang, P. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%AJiménez-Andrade, E. [Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany]%AJiménez-Andrade, E. [Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany]%AGroves, B. [Research School of Astronomy & Astrophysics, Australian National University, Mt. Stromlo Observatory, Cotter Rd, Weston Creek, ACT 2611, Australia]%AGroves, B. [Research School of Astronomy & Astrophysics, Australian National University, Mt. Stromlo Observatory, Cotter Rd, Weston Creek, ACT 2611, Australia]%ALeslie, S. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%ALeslie, S. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany]%ASargent, M. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK]%ASargent, M. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK]%BJournal Name: Monthly Notices of the Royal Astronomical Society; Journal Volume: 491; Journal Issue: 4; Related Information: CHORUS Timestamp: 2020-11-21 20:06:46 %D2019%IOxford University Press %JJournal Name: Monthly Notices of the Royal Astronomical Society; Journal Volume: 491; Journal Issue: 4; Related Information: CHORUS Timestamp: 2020-11-21 20:06:46 %K %MOSTI ID: 10128010 %PMedium: X %TA3COSMOS: the dust attenuation of star-forming galaxies at z  = 2.5–4.0 from the COSMOS-ALMA archive %XABSTRACT

We present an analysis of the dust attenuation of star-forming galaxies at z = 2.5–4.0 through the relationship between the UV spectral slope (β), stellar mass (M*), and the infrared excess (IRX = LIR/LUV) based on far-infrared continuum observations from the Atacama Large Millimeter/sub-millimeter Array (ALMA). Our study exploits the full ALMA archive over the COSMOS field processed by the A3COSMOS team, which includes an unprecedented sample of ∼1500 galaxies at z ∼ 3 as primary or secondary targets in ALMA band 6 or 7 observations with a median continuum sensitivity of 126 $\rm {\mu Jy\, beam}^{-1}$ (1σ). The detection rate is highly mass dependent, decreasing drastically below log (M*/M⊙) = 10.5. The detected galaxies show that the IRX–β relationship of massive (log M*/M⊙ > 10) main-sequence galaxies at z = 2.5–4.0 is consistent with that of local galaxies, while starbursts are generally offset by $\sim 0.5\, {\rm dex}$ to larger IRX values. At the low-mass end, we derive upper limits on the infrared luminosities through stacking of the ALMA data. The combined IRX–M* relation at $\rm {log\, ({\it M}_{\ast }/\mathrm{M}_{\odot })\gt 9}$ exhibits a significantly steeper slope than reported in previous studies at similar redshifts, implying little dust obscuration at log M*/M⊙ < 10. However, our results are consistent with earlier measurements at z ∼ 5.5, indicating a potential redshift evolution between z ∼ 2 and z ∼ 6. Deeper observations targeting low-mass galaxies will be required to confirm this finding.

%0Journal Article