Feedback-regulated star formation in molecular clouds and galactic discs

摘要: We present a two-zone theory for feedback-regulated star formation in galactic discs, consistently connecting the galaxy-averaged law with proceeding giant molecular clouds (GMCs). Our focus is on galaxies gas surface density Sigma_g>~100 Msun pc^-2. In our theory, disc consists of Toomre-mass GMCs embedded volume-filling ISM. Radiation pressure dust disperses and most supernovae explode medium. A derived by balancing momentum input from supernova feedback gravitational weight gas. This good agreement observations CO conversion factor depending continuously Sigma_g. argue that efficiency per free fall time, epsilon_ff^gal, only weak function which convert their into stars. possible because rate limiting step at form: large GMCs, Toomre Q parameter obtains value slightly above unity so GMC consistent law. contrast results other theories turbulence-regulated discuss predictions model. Using compilation data literature, we show time non-universal increases increasing fraction, as predicted also predict fraction mass bound decreases values efficiency. qualitatively smooth distribution inferred local ultra-luminous infrared small clumps high-redshift galaxies.