Colloquium on Dec. 5, 2024

The evolution of star-forming galaxies across cosmic time: a perspective on dust attenuation

Speaker: Xianzhong Zheng (SJTU)

Venue: SWIFAR Building 2111

Time: 16:00 PM, Thursday, Dec. 5, 2024

Abstract:

About half of the radiation energy from cosmic star formation is absorbed and re-emitted by dust into the far-infrared.  Characterizing how galaxy properties shape dust attenuation of star-forming galaxies (SFGs) is essential for understanding baryonic processes underlying galaxy growth, particularly in relation to star formation, chemical enrichment, and structural evolution.  We explored the relationships between dust obscuration (IRX=L_IR/L_UV)  and various galaxy parameters, finding a universal scaling relation relation of IRX for SFGs out to z=3,  jointly determined by star formation rate, galaxy size, metallicity and axial ratio.  We demonstrate that this relationship can be well  modeled using a two-component dust-star model for disk SFGs, where the structure of the diffuse and dense ISM and the dust opacity of HII regions are closely linked to the galaxy's chemical enrichment. However, current-generation hydrodynamic simulations have not succeeded in reproducing this universal IRX relation. The implications of these findings for galaxy evolution will be discussed.

Report PPT:  SWIFAR_Xianzhong Zheng.pdf