Untangling the physical processes that govern galaxy formation and evolution remains a key challenge for astrophysics in the 21st century. Recent observations have pushed galaxy detections to the edge of Cosmic Dawn, within ~300 Myrs of the Big Bang. Hubble has played a crucial role on those developments, starting with the revolutionary images produced by the Hubble Deep Field and progressing through GOODS, COSMOS, CANDELS and CLASH to several iterations of the Hubble Ultra Deep Field. Coupled with multiwavelength data from Chandra, Spitzer, Herschel and other observatories, Hubble’s observations have transformed our understanding of galaxy assembly and set the scene for JWST’s exploration of the end of the dark ages.
Four years after Servicing Mission 4, Hubble retains powerful capabilities. With that in mind, the STScI Director asked the Hubble Deep Fields Initiative (HDFI) working group to identify potential observing opportunities that could advance our knowledge of the early epochs of galaxy formation and perhaps offer a first glimpse of JWST’s universe.