Star formation efficiency and destruction of giant molecular clouds with stellar feedback

speaker: Jeong-Gyu Kim


Galaxy evolution crucially depends on how gas is converted into stars in giant molecular clouds (GMCs) and on how ensuing stellar feedback from young massive stars (in the form of UV radiation, stellar winds, and supernovae) interacts with the surrounding interstellar medium. Observations indicate that GMCs in normal disk galaxies turn only a small fraction of gas mass into stars per free-fall time and over their lifetimes, while clouds in denser environments may form stars more efficiently. Although stellar feedback is believed to play an important role in controlling the efficiency of star formation and cloud lifecycle, details remain elusive. In this talk, I will present results from radiation (M)HD simulations of star-forming GMCs with stellar feedback. I will show how the star formation efficiency and destruction timescale depend on various integrated cloud properties such as surface density, turbulence level, and magnetization, and discuss the relative importance of different feedback mechanisms. We explain the observed star formation rate of the Milky Way by applying our finding that the efficiency per free-fall time decreases with the virial parameter of a molecular cloud. Time permitting, I will also briefly introduce our ongoing effort in modeling multiphase galactic disks with self-consistent star formation and feedback using the TIGRESS numerical framework.