The beast of both worlds: the WEAVE-LOFAR Survey

New radio surveys offer a compelling way of identifying activity in the Universe (whether the activity is due to star formation or accretion onto supermassive black holes), because of their incredible sensitivity, great spatial resolution and because they are impervious to dust extinction. At the same time, new generation massively-multiplexed spectrographs are coming online, offering the chance to simultaneously observe ~1000 sources of interest spread over very wide areas, raising the prospect of game-changing optical spectroscopy of huge statistical samples. In this project, we will bring together the immense power of two world--leading facilities, the Low Frequency Array (LOFAR) and the William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE). By delivering the WEAVE--LOFAR survey, and leading its scientific exploitation, we will use this potent combination to: (i) make unrivalled measurements of the nature of the faint radio source population, (ii) once--and--for-all solve the mystery of the role of stellar mass in driving the relationship between a galaxy's star formation rate and its radio luminosity, and (iii) unambiguously demonstrate the impact of different quenching mechanisms such as feedback from an active galactic nucleus (AGN) on different types of galaxies. This work plan will also ensure that the UK community as a whole can benefit from the new WEAVE-LOFAR dataset containing more than a million hour--long spectra of radio sources.