NGDEEP: The Star Formation and Ionization Properties of Galaxies at $1.7 < z < 3.4$
| Autor: | Shen, Lu, Papovich, Casey, Matharu, Jasleen, Pirzkal, Nor, Hu, Weida, Berg, Danielle A., Bagley, Micaela B., Backhaus, Bren E., Cleri, Nikko J., Dickinson, Mark, Finkelstein, Steven L., Hathi, Nimish P., Huertas-Company, Marc, Hutchison, Taylor A., Giavalisco, Mauro, Grogin, Norman A., Jaskot, Anne E., Jung, Intae, Kartaltepe, Jeyhan S., Koekemoer, Anton M., Lotz, Jennifer M., Pérez-González, Pablo G., Rothberg, Barry, Simons, Raymond C., Vanderhoof, Brittany N., Yung, L. Y. Aaron |
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| Rok vydání: | 2024 |
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| Druh dokumentu: | Working Paper |
| Popis: | We use JWST/NIRISS slitless spectroscopy from the Next Generation Deep Extragalactic Exploratory Public (NGDEEP) Survey to investigate the physical condition of star-forming galaxies at $1.7 < z < 3.4$. At these redshifts, the deep NGDEEP NIRISS slitless spectroscopy covers the [O II]$\lambda\lambda$3726,3729, [O III]$\lambda\lambda$4959,5007, H$\beta$ and H$\alpha$ emission features for galaxies with stellar masses $\log(\mathrm{M_\ast/M_\odot}) \gtrsim 7$, nearly a factor of a hundred lower than previous studies. We focus on the [O III]/[O II] (O$_{32}$) ratio which is primarily sensitive to the ionization state and with a secondary dependence on the gas-phase metallicity of the interstellar medium. We find significant ($\gtrsim5\sigma$) correlations between the O$_{32}$ ratio and galaxy properties as O$_{32}$ increases with decreasing stellar mass, decreasing star formation rate (SFR), increasing specific SFR (sSFR$\equiv \mathrm{SFR}/M_*$), and increasing equivalent width (EW) of H$\beta$ and H$\alpha$. These trends suggest a tight connection between the ionization parameter and these galaxy properties. Galaxies at $z\sim2-3$ exhibit a higher O$_{32}$ than local normal galaxies with the same stellar masses and SFRs, indicating that they have a higher ionization parameter and lower metallicity than local normal galaxies. In addition, we observe an evolutionary trend in the O$_{32}$ -- EW(H$\beta$) relation from $z\sim0$ and $z\gtrsim5$, such that higher redshift galaxies have higher EW(H$\beta$) and higher O$_{32}$ at fixed EW. We argue that both the enhanced recent star formation activity and the higher star formation surface density may contribute to the increase in O$_{32}$ and the ionization parameter. Comment: 27 pages, 14 figures |
| Databáze: | arXiv |
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