In pursuit of giants

I. The evolution of the dust-to-stellar mass ratio in distant dusty galaxies^⋆

¹ SISSA, Via Bonomea 265, Trieste, Italy
e-mail: darko.donevski@sissa.it
² Dunlap Institute for Astronomy & Astrophysics, 50 St. George Street, Toronto, ON M5S 3H4, Canada
³ IFPU – Institute for fundamental Physics of the Universe, Via Beirut 2, 34014 Trieste, Italy
⁴ National Centre for Nuclear Research, ul. Pasteura 7, 02-093 Warsaw, Poland
⁵ Aix Marseille Univ. CNRS, CNES, LAM, Marseille, France
⁶ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁷ AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France
⁸ Institute for Astronomy, Royal Observatory, Edinburgh EH9 3HJ, UK
⁹ University of the Western Cape, Bellville, Cape Town 7535, South Africa
¹⁰ South African Astronomical Observatories, Observatory, Cape Town 7925, South Africa
¹¹ Cosmic Dawn Center (DAWN), Copenhagen, Denmark
¹² Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej, 30-2100 Copenhagen, Denmark
¹³ INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via P. Gobetti 93/3, 40129 Bologna, Italy
¹⁴ Department of Astronomy, University of Florida, 211 Bryant Space Sciences Center, Gainesville, FL, USA
¹⁵ University of Florida Informatics Institute, 432 Newell Drive, CISE Bldg E251, Gainesville, FL 32611, USA

Received: 12 May 2020
Accepted: 15 August 2020

Abstract

The dust-to-stellar mass ratio (M_dust/M_⋆) is a crucial, albeit poorly constrained, parameter for improving our understanding of the complex physical processes involved in the production of dust, metals, and stars in galaxy evolution. In this work, we explore trends of M_dust/M_⋆ with different physical parameters and using observations of 300 massive dusty star-forming galaxies detected with ALMA up to z ≈ 5. Additionally, we interpret our findings with different models of dusty galaxy formation. We find that M_dust/M_⋆ evolves with redshift, stellar mass, specific star formation rates, and integrated dust size, but that evolution is different for main-sequence galaxies than it is for starburst galaxies. In both galaxy populations, M_dust/M_⋆ increases until z ∼ 2, followed by a roughly flat trend towards higher redshifts, suggesting efficient dust growth in the distant universe. We confirm that the inverse relation between M_dust/M_⋆ and M_⋆ holds up to z ≈ 5 and can be interpreted as an evolutionary transition from early to late starburst phases. We demonstrate that the M_dust/M_⋆ in starbursts reflects the increase in molecular gas fraction with redshift and attains the highest values for sources with the most compact dusty star formation. State-of-the-art cosmological simulations that include self-consistent dust growth have the capacity to broadly reproduce the evolution of M_dust/M_⋆ in main-sequence galaxies, but underestimating it in starbursts. The latter is found to be linked to lower gas-phase metallicities and longer dust-growth timescales relative to observations. The results of phenomenological models based on the main-sequence and starburst dichotomy as well as analytical models that include recipes for rapid metal enrichment are consistent with our observations. Therefore, our results strongly suggest that high M_dust/M_⋆ is due to rapid dust grain growth in the metal-enriched interstellar medium. This work highlights the multi-fold benefits of using M_dust/M_⋆ as a diagnostic tool for: (1) disentangling main-sequence and starburst galaxies up to z ∼ 5; (2) probing the evolutionary phase of massive objects; and (3) refining the treatment of the dust life cycle in simulations.