Special Seminar: Thomas Stanton (University of Edinburgh) - Understanding the Chemical Enrichment of the Early Universe with JWST EXCELS

Chemical abundance measurements provide powerful constraints on crucial physical processes and timescales in galaxy evolution. Previously, the majority of observations at high redshifts were only sensitive to the abundance of oxygen but, with the advent of JWST, it is now possible to measure the abundances of multiple elements into the Epoch of Reionization. In this talk, I will present results from the JWST EXCELS survey, focusing on the chemical properties of star forming galaxies across the redshift range 1 < z < 8. First, I will focus on oxygen abundances, which show clear evidence for a redshift-dependent mass metallicity relationship (MZR). I will then discuss empirical evidence for a fundamental metallicity relationship (FMR) within the EXCELS sample and discuss factors driving the offset of high-redshift galaxies from the locally calibrated FMR. Beyond oxygen, I will present multi-element abundance ratios, where we find clear O-enhanced non-solar abundance ratios (i.e., O/Fe, O/Ar) as expected for young, metal-poor systems in the early Universe. I will discuss the remarkable agreement between high-redshift abundance ratios and local stellar archaeological data. Finally, I will comment on how we can understand the evolution of classical emission-line ratios in high-redshift galaxies by accounting for non-solar abundance patterns.

The FCAD Astronomy Seminars cover a wide range of topics with speakers of all career levels, from graduate students and postdocs to faculty. The seminars take place on Wednesdays from 12-1 PM in LGRT 533. All members of the FCAD community are welcome to attend.