Cake Talk by Taylor Hutchison from Texas A&M University

In the myriad observational and theoretical studies surrounding the reionization era (z~15-6), one point becomes abundantly clear: we are still in the discovery phase of galaxies during this time. Our knowledge of galaxies during this epoch is still in its infancy, but what little we know hints that these galaxies emit copious UV radiation, powered by massive stars with low metal content and significant ionization. While the Lyman-alpha line is the UV gold standard for finding galaxies during this epoch, the resonant line is highly sensitive to neutral Hydrogen -- often pushing the redshift derived from this line hundreds of km/s redwards of the true redshift.

However, the rest-UV spectra of galaxies contain a rich variety of nebular metal emission lines which can trace the systemic redshift of these distant sources, and contain highly valuable information about the massive stars and physical conditions in galaxies during this epoch. Such UV nebular lines are targetable at these redshifts, yet have been unexplored except in rare, individual cases. In this talk I will discuss a Keck/MOSFIRE spectroscopic search for rest-UV nebular metal lines in reionization-era galaxies in the CANDELS fields, starting with an analysis of a spectroscopically-confirmed galaxy at z=7.5. I will also show preliminary results from the broader NIR spectroscopic survey searching for multiple rest-UV lines in EoR galaxies. Finally, I will highlight the exciting science that we can expect from observations in the IR using the JWST, opening the door to a new era of high-redshift science.