Dust and galaxy evolution

Hiroyuki Hirashita^1*

¹Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan

* Presenter:Hiroyuki Hirashita, email:hirashita@asiaa.sinica.edu.tw

Dust plays an important role in galaxy evolution. Thus, the evolution of dust in the interstellar medium is one of the key issues in clarifying the galaxy evolution. For the evolution of dust, the dust amount and the dust properties (especially the grain size distribution) are both important. 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. I also talk about our recent efforts of implementing the above dust evolution processes into hydrodynamical galaxy evolution simulations. We have recently implemented dust evolution into a cosmological simulation, based on which we are able to predict the dust evolution over a cosmological time and volume.

Keywords: galaxy evolution, interstellar medium, dust, cosmological simulation