Dayal, P, Ferrara, A, Sommovigo, L, Bouwens, R, Oesch, PA, Smit, R, Gonzalez, V, Schouws, S, Stefanon, M, Kobayashi, C, Bremer, J, Algera, HSB, Aravena, M, Bowler, RAA, da Cunha, E, Fudamoto, Y, Graziani, L, Hodge, J, Inami, H, De Looze, I et al, Pallottini, A, Riechers, D, Schneider, R, Stark, D and Endsley, R (2023) The ALMA REBELS survey: the dust content of z ∼7 Lyman break galaxies. Monthly Notices of the Royal Astronomical Society, 512 (1). pp. 989-1002. ISSN 0035-8711

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Abstract

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 ≃ 7. We find that the galaxy dust mass, Md, is regulated by the combination of SNII dust production, astration, shock destruction, and ejection in outflows; grain growth (with a standard timescale τ0 = 30 Myr) plays a negligible role. The model predicts a dust-to-stellar mass ratio of ∼0.07−0.1 per cent and a UV-to-total star formation rate relation such that log(ψUV) = −0.05 [log(ψ)]2 + 0.86 log(ψ) − 0.05 (implying that 55-80 per cent of the star formation is obscured) for REBELS galaxies with stellar mass M∗=109−10M⊙⁠. 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 (⁠∼0.94−1.1 per cent⁠) that are up to 18 × larger than expected from the fiducial relation. Due to the physical coupling between dust and metal enrichment, even decreasing τ0 to very low values (0.3 Myr) only increases the dust-to-stellar mass ratio by a factor ∼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.

Item Type:	Article
Additional Information:	This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2023Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords:	0201 Astronomical and Space Sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press (OUP)
Date Deposited:	08 Mar 2022 15:18
Last Modified:	21 Mar 2023 15:30
DOI or ID number:	10.1093/mnras/stac537
URI:	https://researchonline.ljmu.ac.uk/id/eprint/16468

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