Colloquium on Mar. 10, 2022

Transition of the initial mass function in the metal-poor environments

Speaker: Chon Sunmyon (Tohoku University)

Venue: Video Conference

Time: 16:00 PM, Thursday, Mar. 10, 2022

Abstract:

The initial mass function (IMF) plays a crucial role in the formation and evolution of the stars and galaxies that we observe today. In the primordial and low-metallicity environments, the nature of the IMF is still poorly understood. Recent numerical simulations have shown that the typical stellar mass is ~several hundred solar mass, which is much larger than those observed in the present-day environments.  This indicates that the IMF transition occurs during the cosmic evolution. In this talk, I would like to review the recent progress on the star formation in the primordial and low-metallicity environments and introduce our recent work on the transition of the IMF in various metallicity environments. By performing three-dimensional hydrodynamics simulations, we have found the IMF transition occurs at Z/Zsun ~ 0.01-0.1. When Z/Zsun < 0.01, a single massive cloud core monolithically collapses to form a massive stellar system. When Z/Zsun = 0.1, a highly filamentary structure develops owing to efficient fine-structure line cooling and the fragmentation of filaments limits the mass supply to the massive stars. We conclude that cooling at the scales of the turbulent motion promotes the development of the filamentary structure and works as an important factor leading to the present-day IMF.

Report PPT:  SWIFAR_ Chon Sunmyon.pdf