UV Diagnostics in Local High-z Analogs with the CLASSY Survey
Matilde Mingozzi (Space Telescope Science Institute)
Tuesday 05/07/2022 @ 14:00, Sala IV piano Battiferro - Presenza + remoto
Rest-frame UV spectra play a key role in the understanding of massive stellar populations, chemical evolution, feedback processes, and reionization. Indeed, in the upcoming JWST era, the UV spectroscopic frontier will be pushed to higher redshifts than ever before, to finally reveal and explore the first galaxies in the distant Universe. In this context, the COS Legacy Archive Spectroscopic SurveY (CLASSY) provides the first high-quality, high-resolution and broad-wavelength range catalogue of 45 local star-forming high-z analogues in the rest-frame UV (1150 - 2000 Å) to investigate their stellar and gas properties. As such, CLASSY provides the ideal FUV atlas with which we can tailor a complete UV diagnostic toolkit to investigate the interstellar medium (ISM) properties. In this talk I will present such a toolkit, obtained from the analysis of the main emission lines of CLASSY spectra (i.e., N IV] 1483,87, C IV 1548,51, He II 1640, O III] 1661,6, Si III] 1882,93, C III] 1907,9). Specifically, here we focus our investigation on dust attenuation, density, temperature, gas-phase metallicity, ionization parameter diagnostics and source of ionization, taking into account the different ionization zones of the ISM. Finally, I will discuss how our UV tool-kit compares to well-known optical diagnostics, analyzing archival optical spectra for all the CLASSY targets. Overall, this set of rest-FUV diagnostics will be crucial to interpret the earliest galaxies that JWST will reveal.