The Dust Enrichment of Galaxies

Interstellar dust plays a key role in the evolution of galaxies, particularly during the star formation process. During their AGB red giant phase of evolution, low and intermediate mass stars are known to be important contributors to the interstellar dust budgets of galaxies like our own. However, massive stars, and their core-collapse (CC) supernovae, could potentially make a significant contribution to the dust budgets of some galaxies, particularly during their earliest stages of evolution.The copious amounts of dust observed in many high-z galaxies are not believed to be produced by low and intermediate mass stars, since the galaxy ages of 1 Gyr or less are too short for significant numbers of AGB stars to be present. Massive stars, and their CC SNe, arising from the starbursts that power these galaxies, are the most plausible sources of their dust. This proposal seeks to renew a current PDRA grant for three years, from September 2009, in order to exploit significant time allocations that have been made for spaceborne studies with Herschel, Spitzer and the HST. These observations, coupled with optimal data reduction procedures and appropriate radiative transfer modelling, can enable a quantification of the contributions of high mass stars and of lower mass stars to the dust enrichment rates of different galaxy types.