Poster Presentation

Dust sources and grain size distributions in high-redshift galaxies

Author(s): Hiroyuki Hirashita (ASIAA)

Presenter: Hiroyuki Hirashita (ASIAA)

ALMA has opened up a window to see the dust enrichment in high-redshift galaxies. However, the major dust source in the early Universe is still being debated. In this talk, I present two of our studies that aimed at constraining the dust sources in the early stage of galaxy evolution. First, we constrained the dust production rate per supernova using a sample of galaxies (LBGs and LAEs) at z > 5 (Hirashita et al. 2017). To derive the dust mass, we performed SED fitting by considering dust extinction and emission (including ALMA data) self-consistently. As a consequence, we obtained an upper limit of dust mass produced per supernova as 0.1 Msun, which is consistent with theoretical dust condensation/destruction calculations. Second, we constructed an evolution model of grain size distribution and applied it to high-redshift LBGs at z > 7 (Liu & Hirashita 2019). The model is calibrated by ALMA data. Based on the grain size distributions, we calculated the extinction curves. As a consequence, we found that the shape of extinction curves highly reflects the major dust source (stellar dust production or dust growth in the interstellar medium). Thus, if we constrain the extinction curves by future JWST observations, we are able to identify the major dust source in high-redshift galaxies.