Completing the HST frontier fields legacy with a magnified cosmic noon

Since the advent of the Hubble Frontier Fields (HFF) campaign more than 5.5 years ago, it has been a great success, combining the power of lensing magnification with deep space-based imaging to provide us with our most sensitive views of the universe. This has been due to both the significant effort put into obtaining high accuracy mass models of the clusters and effort in observing the fields with many different telescopes. While all this investment has been good, there has been comparably little focus in using the HFF clusters to study sources at z<2, at cosmic noon, which not only are brighter, but with spectral features and lines which are readily accessible to current telescopes. To facilitate further z<2 studies, we propose to add deep 0.2 micron imaging observations with the WFC3/UVIS F225W channel to all six HFF clusters, extending the wavelength coverage available with HST from 1.7 microns down to 0.2 microns and enabling tight constraints on the redshifts of star-forming galaxies down to z 1. This opens up an immense range of science on lower-luminosity galaxies at z<2, making it possible to probe the faint-end and possible turn-over of the UV luminosity function to z 1, probing escaping ionizing radiation from galaxies at z 2, expanding the search of tiny star-forming (proto-globular-like) sources down to z 1, and studying star formation and dust properties of galaxies belonging to the targeted clusters (0.3