Abstract

Invited Talk - Splinter DustEvol

Thursday, 12 September 2024, 14:05   (S12)

The interstellar dust properties and their evolution in galaxies

Frédéric GALLIANO
AIM, CEA Paris-Saclay, France

Interstellar dust is a crucial physical component of galaxies, absorbing and re-radiating the light from stars and active galactic nuclei. It plays a major role in the heating and cooling of the InterStellar Medium (ISM), as well as in the growth of its chemical complexity. Yet, the properties of interstellar dust grains, that is their composition, impacting their optical properties, and their size and shape distributions, are currently poorly-known. In addition, there is strong evidence that the microscopic properties of these grains evolve within the ISM, under the effects of UV photons, shocks and accretion of gas atoms. This local evolution, combined with the grain production by supernovae and post-AGB stars, leads to a long-term, cosmic evolution, at the scale of a galaxy. Different galaxies are thus expected to have systematically different, and locally heterogeneous, grain properties. Refining our knowledge of the way these properties vary as a function of their environmental conditions is a major open question, having crucial consequences on galaxy evolution, and on the formation of stars and planetary systems. In the first part of this talk, I will present the current state-of-the-art census about the dust properties in the Milky Way and nearby galaxies. I will give an overview of the different observables we have access to, as well as the insights from laboratory experiments, and show the uncertainties and degeneracies that we are still facing. I will discuss the challenges of modeling the grain properties of external galaxies. In the second part, I will review the empirical evidence of dust evolution in the ISM. I will discuss the theoretical models that simulate these processes. I will then talk about cosmic dust evolution and its implication for galaxy evolution. I will end with sketching what the future IR probes and UV observatories could bring to this field, as well as the prospect of quantum computers.