Oral Presentation

Evolution of grain size distribution in galaxies

Author(s): Hiroyuki Hirashita (ASIAA)

Presenter: Hiroyuki Hirashita (ASIAA)

The evolution of dust in the interstellar medium is one of the most important aspects in galaxy evolution. For the evolution of dust, it is important to clarify the dust amount and the dust properties (especially the grain size distribution). We modeled the evolution of these two aspects in a consistent framework and proposed the following dust evolution scenario: Dust formation in stellar ejecta is important for the dust enrichment in the early stage of galaxy evolution or in the metal-poor phase. The subsequent evolutions of dust amount and grain size distribution are governed by interstellar processing of dust. Especially, grain disruption by shattering and dust growth by accretion enhance the abundance of small grains while coagulation pushes those created small grains to large sizes. We also show that the above processes governing dust evolution have a variety of impacts on some observable quantities such as extinction curves. Finally, we show our recent efforts of implementing the above dust evolution model in a hydrodynamical simulation.