학술논문
The Physical Conditions of Emission-Line Galaxies at Cosmic Dawn from JWST/NIRSpec Spectroscopy in the SMACS 0723 Early Release Observations
Document Type
Working Paper
Author
Trump, Jonathan R.; Haro, Pablo Arrabal; Simons, Raymond C.; Backhaus, Bren E.; Amorín, Ricardo O.; Dickinson, Mark; Fernández, Vital; Papovich, Casey; Nicholls, David C.; Kewley, Lisa J.; Brunker, Samantha W.; Salzer, John J.; Wilkins, Stephen M.; Almaini, Omar; Bagley, Micaela B.; Berg, Danielle A.; Bhatawdekar, Rachana; Bisigello, Laura; Buat, Véronique; Burgarella, Denis; Calabrò, Antonello; Casey, Caitlin M.; Ciesla, Laure; Cleri, Nikko J.; Cole, Justin W.; Cooper, M. C.; Cooray, Asantha R.; Costantin, Luca; Ferguson, Henry C.; Finkelstein, Steven L.; Fujimoto, Seiji; Gardner, Jonathan P.; Gawiser, Eric; Giavalisco, Mauro; Grazian, Andrea; Grogin, Norman A.; Hathi, Nimish P.; Hirschmann, Michaela; Holwerda, Benne W.; Huertas-Company, Marc; Hutchison, Taylor A.; Jogee, Shardha; Juneau, Stéphanie; Jung, Intae; Kartaltepe, Jeyhan S.; Kirkpatrick, Allison; Koekemoer, Anton M.; Lotz, Jennifer M.; Lucas, Ray A.; Magnelli, Benjamin; Matharu, Jasleen; Pérez-González, Pablo G.; Pirzkal, Nor; Rafelski, Marc; Rose, Caitlin; Seillé, Lise-Marie; Somerville, Rachel S.; Straughn, Amber N.; Tacchella, Sandro; Vanderhoof, Brittany N.; Weiner, Benjamin J.; Wuyts, Stijn; Yung, L. Y. Aaron; Zavala, Jorge A.
Source
Subject
Language
Abstract
We present rest-frame optical emission-line flux ratio measurements for five $z>5$ galaxies observed by the JWST Near-Infared Spectrograph (NIRSpec) in the SMACS 0723 Early Release Observations. We add several quality-control and post-processing steps to the NIRSpec pipeline reduction products in order to ensure reliable relative flux calibration of emission lines that are closely separated in wavelength, despite the uncertain \textit{absolute} spectrophotometry of the current version of the reductions. Compared to $z\sim3$ galaxies in the literature, the $z>5$ galaxies have similar [OIII]$\lambda$5008/H$\beta$ ratios, similar [OIII]$\lambda$4364/H$\gamma$ ratios, and higher ($\sim$0.5 dex) [NeIII]$\lambda$3870/[OII]$\lambda$3728 ratios. We compare the observations to MAPPINGS V photoionization models and find that the measured [NeIII]$\lambda$3870/[OII]$\lambda$3728, [OIII]$\lambda$4364/H$\gamma$, and [OIII]$\lambda$5008/H$\beta$ emission-line ratios are consistent with an interstellar medium that has very high ionization ($\log(Q) \simeq 8-9$, units of cm~s$^{-1}$), low metallicity ($Z/Z_\odot \lesssim 0.2$), and very high pressure ($\log(P/k) \simeq 8-9$, units of cm$^{-3}$). The combination of [OIII]$\lambda$4364/H$\gamma$ and [OIII]$\lambda$(4960+5008)/H$\beta$ line ratios indicate very high electron temperatures of $4.1<\log(T_e/{\rm K})<4.4$, further implying metallicities of $Z/Z_\odot \lesssim 0.2$ with the application of low-redshift calibrations for ``$T_e$-based'' metallicities. These observations represent a tantalizing new view of the physical conditions of the interstellar medium in galaxies at cosmic dawn.
Comment: Accepted for publication in AAS Journals. 14 pages, 6 figures, 3 tables
Comment: Accepted for publication in AAS Journals. 14 pages, 6 figures, 3 tables