An Unbiased View of the Physical Drivers of Star Formation over Cosmic Time

The most fundamental measurements for galaxy evolution studies are the evolution of the cosmic star-formation rate density as a function of cosmic time and the distribution of the star-formation rate density amongst the galaxy population at each epoch. Current studies of star formation at high redshifts are almost ubiquitously based on the ultraviolet continuum emission; however, this is heavily affected by dust extinction, requiring large and uncertain corrections. This project is focussed on using alternative, dust independent, techniques to make these critical measurements in a robust manner, using large and unbiased samples of star-forming galaxies out to the highest redshifts. Samples of H-alpha-selected star-forming galaxies will be drawn from JWST narrow-band imaging to probe lower-luminosity star formation back to the highest redshifts. In addition, radio observations from a 5-yr large programme with LOFAR will be used to obtain the deepest, wide-area radio survey in the best-studied extragalactic fields, augmented by dedicated optical spectroscopy of all (~240k) detected radio sources using the new WEAVE spectrograph. This will determine the distribution of star-formation as independent functions of galaxy mass, environment and redshift, out to the peak epoch of star formation activity at z~2, and enable a global measure of the star formation rate density back to the Epoch of Reionisation.