In this talk, I will present results from the latest version of L-GALAXIES, a galaxy evolution simulation which now includes binary stellar evolution (using binary_c) and dust production & destruction. Through its sophisticated galactic chemical evolution modelling, L-GALAXIES can provide a comprehensive overview of the total metal and dust content in the Universe, separated into various astrophysical “phases” (e.g. stars, molecular clouds, neutral interstellar medium, and diffuse circumgalactic medium). By comparing this to observations, we can help provide constraints on the small-scale models used in simulations for stellar nucleosynthesis, stellar feedback, and dust production (including supernovae, binary-star phenomena, and grain growth).

First, I will present the evolution of the cosmic metal density in L-GALAXIES back to z~6, compared to observations of the neutral ISM from damped Lyman-alpha (DLA) systems. Second, I will show the complimentary evolution of the cosmic dust mass density in L-GALAXIES across the same period, compared to dust observations from SED fitting and DLA absorption-line spectra. Third, I will combine these to provide an overall census of the dust and metal content in various phases of galaxies as a function of their stellar mass.

These analyses reveal three key findings: (a) simulations must allow significant ejection of metals and dust out of galaxies via supernova-driven winds, (b) simulations may also need to be recalibrated at high redshift to account for the dust-obscured star formation now observed, and (c) DLA observations may over-estimate the metal and dust budget of the Universe due to biased sampling.