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arXiv · 2410.03784

Emission-Line Ratios and Ionization Conditions of CEERS Star-Forming Galaxies with JWST/NIRSpec

Ansh R. Gupta·Allison Kirkpatrick·Vital Fernandez·Pablo Arrabal Haro·Bren E. Backhaus·Nikko J. Cleri·Norman A. Grogin·Anton M. Koekemoer
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Abstract

Galaxy emission-line fluxes can be analyzed to determine star formation rates (SFR) and ISM ionization. Here, we investigate rest-frame optical emission lines of 71 star-forming galaxies at redshift 0.7 < z < 7 from the Cosmic Evolution Early Release Science (CEERS) survey using JWST/NIRSpec. We use H$α$ line fluxes to measure SFRs. We combine these with HST CANDELS stellar mass estimates to determine the redshift evolution of specific SFR (sSFR) and compare our sample with the star-forming galaxy main sequence. We create [O III]$λ$5008/H$β$ versus [Ne III]$λ$3870/[O II]$λ$3728 line ratio diagrams and correlate these ratios with sSFR and the distance of each galaxy from the main sequence (excess sSFR). We find a modest correlation between the line ratios and sSFR, which is consistent with previous work analyzing similar samples. However, we find a weak correlation between the line ratios and excess sSFR. Taken together, our results suggest that sSFR is the parameter that governs ionization conditions rather than SFR or a galaxy's distance from the main sequence. These measurements reveal a rich diversity of ISM conditions and physical galaxy properties throughout cosmic time.

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Ansh R. Gupta, Allison Kirkpatrick, Vital Fernandez, Pablo Arrabal Haro, Bren E. Backhaus, Nikko J. Cleri, Norman A. Grogin, Anton M. Koekemoer. 2024-10-03. Emission-Line Ratios and Ionization Conditions of CEERS Star-Forming Galaxies with JWST/NIRSpec. https://arxiv.org/abs/2410.03784

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