First submission -540248356 Assigned ID: 821 ----- Attempting Submission 1 (Fri Mar 06 21:51:35 GMT 2020) ----- Extragalactic metallicities are primarily inferred through studies of the neutral and ionized gas (H I and H II). We propose to obtain accurate metallicities and ages from the integrated light of young star clusters for an archival sample of 12 nearby star-forming galaxies. The neutral and ionized gas contained in our galaxy sample has been amply studied in the UV and optical range. We will be able to directly compare H I and H II metallicity diagnostics with those determined from the stellar component in the UV with the ultimate goal to provide the first quantitative conversion between stellar, neutral- and ionized-gas diagnostics. We will investigate the chemical composition of the different components (stars and multi-phase gas) as a function of galactic properties. Now more than ever it is critical to acquire a better understanding of UV spectra as this will be the only wavelength regime accessible for high-z studies (z~3-8) with the upcoming space- and ground-based facilities (JWST, TMT, ELT). The UV analysis here proposed will create a metallicity benchmark against which future high-z stellar population observations can be compared, allowing us not only to probe the earliest galactic environments (stars+gas), but also galactic chemical evolution through cosmic time. The principal investigator Dr. Hernandez is an expert on COS observations having previously served as a Research and Instrument Analyst for the COS instrument team for three years. Her expertise, reflected in her leadership and/or collaboration in at least 12 scientific articles in the last five years, expands from data reduction to scientific projects relying primarily on COS data. Furthermore, her main field of research has focused on chemical abundances of star clusters, and is expanding to the interstellar medium in order to understand the chemical histories of galaxies at different times. Dr. Aloisi's expertise includes the analysis of spectroscopic observations to obtain column densities and chemical abundances of both the gas, and stellar components in extragalactic environments. One of Dr. Aloisi's primary fields of technical expertise is in UV spectroscopy with space-based telescopes. For years she led the COS+STIS Team, acquiring knowledge on the strengths and weaknesses of the spectrographs. Her experience in both the scientific and technical areas are critical for the success of this project. Dr. James has extensively investigated the abundances of both the neutral gas (UV spectroscopy) and the ionized gas (IFU observations). She is also a the deputy of the COS Team at STScI, with ample knowledge on data reduction and analysis of COS observations. Dr. Larsen was the original creator of the L12 technique described in our proposal. His expertise includes analysis of spectroscopic observations to measure the chemical composition of galaxies in order to understand their chemical evolution. His contribution on stellar population modeling (atmospheres and synthesis) are invaluable to achieve our goals. Stellar Populations and the Interstellar Medium Galaxies 0 Regular false false false false false SUPPORTED