Description
Recent JWST observations of high-redshift galaxies, as well as spectroscopic and dynamical studies of nearby early-type galaxies, signal deviations of the stellar initial mass function (IMF) from the form inferred in the Solar neighbourhood. We present results from COLIBRE simulations run with a version of the code adapted to allow the formation of stellar populations with a non-universal IMF, in which metal yields and the energetics of supernova feedback are self-consistently adjusted. Here we choose to make the IMF increasingly top heavy (i.e. weighted more towards massive stars) for stellar populations that form from natal gas of high mass density. The model we have applied yields an elevated far-UV luminosity in young stellar populations without significantly impacting the star formation rate, resulting in high redshift (z > 10) UV luminosity functions that are in strong agreement with recent data from JWST.
