New Metallicity Diagnostics for High-Redshift Star-Forming Galaxies

We have modelled the ultraviolet spectra of star-forming regions at metallicities between 1/20 and twice solar, by integrating the output from the model atmosphere code WM-BASIC into the spectral synthesis code STARBURST99. Using our model spectra, we have identified a promising new metallicity diagnostic for high-redshift star-forming galaxies, based upon the strength of a blend of photospheric FeIII absorption lines between 1935 and 2020 angstrom. We test its validity by applying it to two well-observed high-redshift galaxies.