Speaker
Description
Reionization marks the last major phase transition of matter in the Universe and its completion had crucial impact on the formation of the smallest galaxies. While reionization roughly encapsulated the first Gyr of cosmic time, the precise timing, topology and the sources of ionizing photons are unknown. In my talk, I will mainly present results on the spectroscopic properties of galaxies in the early Universe from the EIGER and ALT surveys, which total ~180 hrs of JWST/NIRCam imaging and wide-field slitless spectroscopy in the fields of high-redshift luminous quasars and the Abell 2744 lensing cluster. I will show how we used these data to confirm redshifts for ~2000 galaxies at z=3-9, and simultaneously measured their distributions of star formation rate, mass, metallicity, UV colours and line equivalent widths. I will also present our results on the abundance and properties of faint AGN at high redshift, and discuss the current insights on their importance for understanding supermassive black hole formation and their role in cosmic reionization. Finally, I will highlight avenues to address current fundamental limitations in our understanding of the role of galaxies in the reionization of the Universe with new and future VLT programs focussed on the Lyman-alpha emission-line, including the first galaxy tomographic study at high-redshift in the MUSE eXtremely Deep Field.
