Knocking on giants' doors: I. The evolution of the dust-to-stellar mass ratio in distant dusty galaxies

Abstract

The dust-to-stellar mass ratio ($M_{\mathrm{dust}}$/$M_{\star }$) is a crucial yet poorly constrained quantity to understand the production mechanisms of dust, metals and stars in galaxy evolution. In this work we explore and interpret the nature of $M_{\mathrm{dust}}$/$M_{\star }$ in 300 massive ($M_{\star }>10^{10}{M}_{\odot }$), dusty star-forming galaxies detected with ALMA up to $z\approx 5$. We find that $M_{\mathrm{dust}}$/$M_{\star }$ evolves with redshift, stellar mass, specific SFR and integrated dust size, differently for main sequence and starburst galaxies. In both galaxy populations $M_{\mathrm{dust}}$/$M_{\star }$ rises until $z\sim 2$ followed by a roughly flat trend towards higher redshifts. We show that the inverse relation between $M_{\mathrm{dust}}$/$M_{\star }$ and $M_{\star }$ holds up to $z\approx 5$ and can be interpreted as an evolutionary transition from early to late starburst phases. We demonstrate that $M_{\mathrm{dust}}$/$M_{\star }$ in starbursts mirrors the increase in molecular gas fraction with redshift, and is enhanced in objects with the most compact dusty star-formation. The state-of-the-art cosmological simulation SIMBA broadly matches the evolution of $M_{\mathrm{dust}}$/$M_{\star }$ in main sequence galaxies, but underestimates it in starbursts. The latter is found to be linked to lower gas-phase metallicities and longer dust growth timescales relative to data. Our data are well reproduced by analytical model that includes recipes for rapid metal enrichment, strongly suggesting that high $M_{\mathrm{dust}}$/$M_{\star }$ is due to fast grain growth in metal enriched ISM. Our work highlights multifold benefits of using $M_{\mathrm{dust}}$/$M_{\star }$ as a diagnostic tool for: (1) separating main sequence and starburst galaxies until $z\sim 5$; (2) probing the evolutionary phases of dusty galaxies, and (3) refining the treatment of dust life cycle in simulations.

Accepted for publication in A&A, main text 17 pages, 9 figures