Recent observations by James Webb Space Telescope discovered a number of high-redshift galaxies with strong emission lines from doubly ionized oxygen. Combined with ALMA observations of far-infrared lines, multi-line diagnostics can be applied to the high-redshift galaxies in order to probe the physical conditions of the inter-stellar medium. We study the formation and evolution of galaxies using the FirstLight simulation suite, which provides outputs of 62 high-resolution, zoom-in galaxy simulations. We devise a physical model of HII regions and calculate spatially resolved [OIII] line emission. We show that massive galaxies with stellar masses of M∗>109M⊙ chemically evolve rapidly to z=9. Young stellar populations in the star-forming galaxies boost the [OIII] line emission, rendering the ratio of line luminosity to star formation rate larger than that for low-redshift galaxies, which is consistent with recent observations. Measuring the flux ratios of rest-frame optical and far-infrared lines allows us to estimate the physical conditions such as density and metallicity of the star-forming gas in high-redshift [OIII] emitters.
@article{arxiv.2301.02416,
title = {Simulations of high-redshift [OIII] emitters: Chemical evolution and multi-line diagnostics},
author = {Yurina Nakazato and Naoki Yoshida and Daniel Ceverino},
journal= {arXiv preprint arXiv:2301.02416},
year = {2023}
}