Dust Depletion Near and Far
Abstract
Dust grains play an important role in galaxy ecosystems from the very smallest scales in the interstellar medium through photoelectric heating all the way to the global galactic scales through reprocessing of UV photons into infrared photons. These tiny dust particles have enormous impacts on our interpretations of observed galaxies near and far yet we know surprisingly little about their physical and chemical properties and even less about their formation mechanisms. One very powerful way of studying dust grains is through their various emission lines in the infrared. However, the needed infrared spectra are very difficult to obtain for distant galaxies. A complementary method is to study the gas phase abundances of various metal species which allows us to deduce the amount of metals that have been depleted out of the gas phase and incorporated into solid dust grains. In this talk, I will present an overview of how we infer the depletion of various chemical elements in the interstellar medium of the Milky Way and of distant galaxies and how we can use this to constrain the dust grain composition. Lastly, I will also present a few preliminary studies of how we can use extinction curves to further constrain the dust properties inferred from the depletion measurements.