Dust in cold and warm dark matter in a suite of zoom-in simulations of Milky Way analogues

Abstract We use a suite of hydrodynamical zoom-in simulations of Milky Way analogues to investigate how previously identified trends in dust properties of galaxies can be utilised to infer the underlying dark matter model. We use a sample of 24 comparison simulations comparing a cold dark matter (CDM) and 3.5 keV warm dark matter (WDM) particle, primarily using a dust-to-metals (DTM) ratio to post-process the dust in the simulation, with alternative methods explored. We find a preference for higher dust masses in CDM over WDM, with a median increase of 6.6 per cent in the CDM sample at redshift z = 0, and with a peak median difference of 25 per cent at z ≈ 0.25. Both CDM and WDM samples are highly concentrated, with approximately 90 per cent of the dust located in the inner region of the halo, though slightly higher in CDM. Contrary to previous work, we find that the Gini coefficient does not consistently show a difference in comparisons of dark matter models, with differences primarily driven by high sensitivity to the unique structure of individual haloes. Finally, we conduct an analysis of some common dust scaling relations, finding that the differences between the two samples in the dust-to-stellar mass and dust-to-SFR functions do not constitute a statistically significant difference at z = 0 with any dust production mechanism. However, at redshifts where the difference in dust mass is greatest, the alternative dust production methods show larger separations between CDM and WDM samples in total mass and scaling relations.