The First Billion Years of the Universe: Five Questions in Five Days

Organizers:

Desika Narayanan, University of Florida
Erica Nelson, University of Colorado Boulder
Pascal Oesch, University of Geneva
Alexandra Pope, University of Massachusetts Amherst

In 2026, it will have been 10 years since the last major conference at the ACP about galaxy formation during the first billion years of the Universe’s history. In this interval, the emergence of JWST and ALMA have shifted the knowledge-space from relatively mature galaxies some 1 billion years after the Big Bang to the emergence of the first, nearly chemically pristine galaxies likely undergoing their first bursts of star formation a full 700 Myr earlier. The result from these observations is a complete upending of our understanding of the formation of the first galaxies in the Universe. Because of this, we will host a conference at the ACP one decade later, to critically examine 5 emerging challenges in the Epoch of First Light. The major goal of this workshop is to accelerate the community toward finding answers to each of the following 5 outstanding puzzles:

• Why are galaxies producing such copious numbers of ultraviolet photons at early times?
• What is the physical nature of Little Red Dots?
• How does dust grow from nearly dust-free systems to 10^7 Msun in just 500 Myr?
• What drives the first quenching episodes in the Universe?
• What is the solution to the photon budget crisis during the Epoch of Reionization?