University of Hertfordshire

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From the same journal

By the same authors

The ALMA REBELS Survey: the dust content of $z \sim 7$ Lyman Break Galaxies

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  • 2202.11118v1

    Accepted author manuscript, 866 KB, PDF document

  • P. Dayal
  • A. Ferrara
  • L. Sommovigo
  • R. Bouwens
  • P. A. Oesch
  • R. Smit
  • V. Gonzalez
  • S. Schouws
  • M. Stefanon
  • J. Bremer
  • H. S. B. Algera
  • M. Aravena
  • R. A. A. Bowler
  • E. da Cunha
  • Y. Fudamoto
  • L. Graziani
  • J. Hodge
  • H. Inami
  • I. De Looze
  • A. Pallottini
  • D. Riechers
  • R. Schneider
  • D. Stark
  • R. Endsley
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Original languageEnglish
JournalMonthly Notices of the Royal Astronomical Society
Publication statusPublished - 22 Feb 2022


We include a fully coupled treatment of metal and dust enrichment into the Delphi semi-analytic model of galaxy formation to explain the dust content of 13 Lyman Break Galaxies (LBGs) detected by the Atacama Large millimetre Array (ALMA) REBELS Large Program at $z\simeq 7$. We find that the galaxy dust mass, $M_d$, is regulated by the combination of SNII dust production, astration, shock destruction, and ejection in outflows; grain growth (with a standard timescale $\tau_0= 30$ Myr) plays a negligible role. The model predicts a dust-to-stellar mass ratio of $\sim 0.07-0.1\%$ and a UV-to-total star formation rate relation such that $log (\psi_{\rm UV}) = -0.05 ~[log (\psi)]^{2} + 0.86 ~log(\psi) -0.05$ (implying that 55-80\% of the star formation is obscured) for REBELS galaxies with stellar mass $M_* = 10^{9-10} M_\odot$. This relation reconciles the intrinsic UV luminosity of LBGs with their observed luminosity function at $z=7$. However, 2 out of the 13 systems show dust-to-stellar mass ratios ($\sim 0.94-1.1\%$) that are up to $18\times$ larger than expected from the fiducial relation. Due to the physical coupling between dust and metal enrichment, even decreasing $\tau_0$ to very low values (0.3 Myr) only increases the dust-to-stellar mass ratio by a factor $ \sim 2$. Given that grain growth is not a viable explanation for such high observed ratios of the dust-to-stellar mass, we propose alternative solutions.


Accepted to MNRAS

ID: 27087134