colloquium – Mario Llerena: Probing the extreme ISM of extreme emission line galaxies at z~4-9

Over the past decades, several studies have discovered a population of galaxies that undergo very strong star formation events. They are called extreme emission line galaxies (EELGs) and are characterized by typically high EWs which are driven by elevated specific star formation rates in low mass galaxies with subsolar metallicities and little dust. Such extreme systems are rare in the local universe, but the number density of EELGs increases with increasing redshift. Such starburst galaxies are currently presumed strongly to be the main drivers of Hydrogen reionization over 5.5 < z < 15, which serves to motivate many of the searches for high-z EELGs as well. I will present the physical properties of a sample of ~1000 EELGs at 4<z<9 photometrically-selected in the CEERS surveys using JWST/NIRCam and templates of local EELGs. Our results suggest they are metal-poor young starbursts with high ionization conditions which indicates they are strong LyC leakers candidates and ideal laboratories to NIRSpec follow-ups to study such extreme ISM conditions.