1. First Sample of H$α$+[O III] $λ$5007 Line Emitters at $z > 6$ Through JWST/NIRCam Slitless Spectroscopy: Physical Properties and Line Luminosity Functions
- Author
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Sun, Fengwu, Egami, Eiichi, Pirzkal, Nor, Rieke, Marcia, Baum, Stefi, Boyer, Martha, Boyett, Kristan, Bunker, Andrew J., Cameron, Alex J., Curti, Mirko, Eisenstein, Daniel J., Gennaro, Mario, Greene, Thomas P., Jaffe, Daniel, Kelly, Doug, Koekemoer, Anton M., Kumari, Nimisha, Maiolino, Roberto, Maseda, Michael, Perna, Michele, Rest, Armin, Robertson, Brant E., Schlawin, Everett, Smit, Renske, Stansberry, John, Sunnquist, Ben, Tacchella, Sandro, Williams, Christina C., and Willmer, Christopher N. A. more...
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Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences - Abstract
We present a sample of four emission-line galaxies at $z=6.11-6.35$ that were serendipitously discovered using the commissioning data for the JWST/NIRCam wide-field slitless spectroscopy (WFSS) mode. One of them (at $z=6.11$) has been reported previously while the others are new discoveries. These sources are selected by the secure detections of both [O III] $λ$5007 and H$α$ lines with other fainter lines tentatively detected in some cases (e.g., [O II] $λ$3727, [O III] $λ$4959). In the [O III]/H$β$ - [N II]/H$α$ Baldwin-Phillips-Terlevich diagram, these galaxies occupy the same parameter space as that of $z\sim2$ star-forming galaxies, indicating that they have been enriched rapidly to sub-solar metallicities ($\sim$0.4 $Z_{\odot}$), similar to galaxies with comparable stellar masses at much lower redshifts. The detection of strong H$α$ lines suggests a higher ionizing photon production efficiency within galaxies in the early Universe. We find brightening of the [O III] $λ$5007 line luminosity function (LF) from $z=3$ to 6, and weak or no redshift evolution of the H$α$ line LF from $z=2$ to 6. Both LFs are under-predicted at $z\sim6$ by a factor of $\sim$10 in certain cosmological simulations. This further indicates a global Ly$α$ photon escape fraction of 7-10% at $z\sim6$, slightly lower than previous estimates through the comparison of the UV-derived star-formation rate density and Ly$α$ luminosity density. Our sample recovers $66^{+128}_{-44}$% of $z=6.0-6.6$ galaxies in the survey volume with stellar masses greater than $5\times10^8$ $M_{\odot}$, suggesting the ubiquity of strong H$α$ and [O III] line emitters in the Epoch of Reionization, which will be further uncovered in the era of JWST., 26 pages, 11 figures, accepted for publication in ApJ on May 11, 2023 more...
- Published
- 2022
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