Abstract

I will present a review of recent progress in our understanding of the star-formation history of the Universe, with special emphasis on how our knowledge of star formation in the first 2 billion years has been improved by the deepest near-infrared images obtained with the Hubble Space Telescope (HST). After describing our current knowledge of comoving star-formation density out to redshifts z=3, I will highlight the impact of the Hubble Ultra Deep Field (HUDF) 2012 campaign, both in discovering the most distant known galaxies, and in improving our knowledge of the evolution of UV luminosity density at early times. I will then explore the extent to which these results are consistent with the requirements for cosmic reionization, and with new measurements of the growth of stellar mass density. Much of the remaining confusion and uncertainty is related to the evolution of the dust properties of galaxies, and so I will conclude with a discussion of our planned ALMA Cycle-1 millimetre imaging of the HUDF . This first deep ALMA mosaic should be an important step towards completing our understanding of cosmic star-formation history.