2019/04/30 by Aswin P. Vijayan, Scott J. Clay, Peter A. Thomas +3 · 1 citation
Physics and Astronomy · #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stz1948
19 pages, 16 figures. Edits: Corrected equation 15 and its parameters. Accepted in MNRAS
arxiv created 2019/07/05 · arxiv updated 2019/07/24
We implement a detailed dust model into the L-Galaxies semi-analytical model which includes: injection of dust by type II and type Ia supernovae (SNe) and AGB stars; grain growth in molecular clouds; and destruction due to supernova-induced shocks, star formation, and reheating. Our grain growth model follows the dust content in molecular clouds and the inter-cloud medium separately, and allows growth only on pre-existing dust grains. At early times, this can make a significant difference to the dust growth rate. Above z∼8, type II SNe are the primary source of dust, whereas below z∼8, grain growth in molecular clouds dominates, with the total dust content being dominated by the latter below z∼6. However, the detailed history of galaxy formation is important for determining the dust content of any individual galaxy. We introduce a fit to the dust-to-metal (DTM) ratio as a function of metallicity and age, which can be used to deduce the DTM ratio of galaxies at any redshift. At z\lesssim3, we find a fairly flat mean relation between metallicity and the DTM, and a positive correlation between metallicity and the dust-to-gas (DTG) ratio, in good agreement with the shape and normalisation of the observed relations. We also match the normalisation of the observed stellar mass -- dust mass relation over the redshift range of 0-4, and to the dust mass function at z=0. Our results are important in interpreting observations on the dust content of galaxies across cosmic time, particularly so at high redshift.