CLASSY XI: Tracing Neutral Gas Properties using UV Absorption Lines and 21-cm Observations
| Autor: | Parker, Kaelee S., Berg, Danielle A., Gazagnes, Simon, Chisholm, John, James, Bethan L., Hayes, Matthew, Heckman, Timothy, Henry, Alaina, Berg, Michelle A., Arellano-Cordova, Karla Z., Xu, Xinfeng, Erb, Dawn K., Martin, Crystal L., Hu, Weida, Skillman, Evan D., McQuinn, Kristen B. W., Chen, Zuyi, Stark, Dan P. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Rest-frame far-ultraviolet (FUV) observations from JWST are revolutionizing our understanding of the high-z galaxies that drove reionization and the mechanisms by which they accomplished it. To fully interpret these observations, we must be able to diagnose how properties of the interstellar medium (ISM; e.g., column density, covering fraction, outflow velocity) directly relate to the absorption features produced. Using the high-S/N and high-resolution FUV spectra of 45 nearby star-forming galaxies from CLASSY, we present the largest uniform, simultaneous characterization of neutral and low-ionization state (LIS) interstellar UV absorption lines (OI, SiII, SII, CII, AlII) across a wide range of galaxy properties. We also present 21-cm HI observations for 35 galaxies, multiple of which are gas-poor or non-detected, possibly indicating the onset of a post-starburst phase. We find that our simultaneous 1-component Voigt profile fits are capable of accurately modeling the LIS absorption for ~75% of galaxies, mitigating challenges associated with saturation, infilling, and degeneracies. While the most massive galaxies require additional components, our 1-component fits return average properties of the absorbing gas and follow the scaling relations described by a single gas cloud. We explore connections between LIS absorption and direct tracers of the neutral ISM (OI, Ly-alpha, HI 21-cm), finding that CII most closely traces the neutral gas trends while other ions exhibit weaker correlations. Given the challenges with directly observing HI at higher-z, we demonstrate that LIS absorption can be a powerful means to study the neutral ISM and present empirical relationships for predicting neutral gas properties. Comment: 25 pages with 16 figures and 2 tables. Long appendix with figure sets and tables. Accepted to ApJ |
| Databáze: | arXiv |
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