Spectroscopic Confirmation of CEERS NIRCam-selected Galaxies at z ≃ 8-10
Date Issued
2023
Author(s)
Arrabal Haro, Pablo
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Finkelstein, Steven L.
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Fujimoto, Seiji
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Fernández, Vital
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Kartaltepe, Jeyhan S.
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Jung, Intae
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Cole, Justin W.
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Burgarella, Denis
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Chworowsky, Katherine
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Hutchison, Taylor A.
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Morales, Alexa M.
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Papovich, Casey
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Simons, Raymond C.
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Amorín, Ricardo O.
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Backhaus, Bren E.
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Bagley, Micaela B.
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•
•
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Cleri, Nikko J.
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Davé, Romeel
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Dekel, Avishai
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Ferguson, Henry C.
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Gawiser, Eric
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Giavalisco, Mauro
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Harish, Santosh
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Hathi, Nimish P.
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Holwerda, Benne W.
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Huertas-Company, Marc
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Koekemoer, Anton M.
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Larson, Rebecca L.
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Lucas, Ray A.
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Mobasher, Bahram
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Pérez-González, Pablo G.
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Pirzkal, Nor
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Rose, Caitlin
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Trump, Jonathan R.
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de la Vega, Alexander
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Wang, Xin
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Weiner, Benjamin J.
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Wilkins, Stephen M.
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Yang, Guang
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Yung, L. Y. Aaron
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Zavala, Jorge A.
Abstract
We present JWST/NIRSpec prism spectroscopy of seven galaxies selected from Cosmic Evolution Early Release Science (CEERS) survey NIRCam imaging with photometric redshifts z phot > 8. We measure emission line redshifts of z = 7.65 and 8.64 for two galaxies. For two other sources without securely detected emission lines we measure $z={9.77}_{-0.29}^{+0.37}$ and ${10.01}_{-0.19}^{+0.14}$ by fitting model spectral templates to the prism data, from which we detect continuum breaks consistent with Lyα opacity from a mostly neutral intergalactic medium. The presence of strong breaks and the absence of strong emission lines give high confidence that these two galaxies have redshifts z > 9.6, but the redshift values derived from the breaks alone have large uncertainties given the low spectral resolution and relatively low S/N of the CEERS NIRSpec prism data. The two z ~ 10 sources observed are relatively luminous (M UV < -20), with blue continua (-2.3 ≲ β ≲ -1.9) and low dust attenuation ( ${A}_{V}\simeq {0.15}_{-0.1}^{+0.3}$ ); and at least one of them has a high stellar mass for a galaxy at that redshift ( $\mathrm{log}({M}_{\star }/{M}_{\odot })\simeq {9.3}_{-0.3}^{+0.2}$ ). Considered together with spectroscopic observations of other CEERS NIRCam-selected high-z galaxy candidates in the literature, we find a high rate of redshift confirmation and low rate of confirmed interlopers (8%). Ten out of 35 z > 8 candidates with CEERS NIRSpec spectroscopy do not have secure redshifts, but the absence of emission lines in their spectra is consistent with redshifts z > 9.6. We find that z > 8 photometric redshifts are generally in agreement (within their uncertainties) with the spectroscopic values, but also that the photometric redshifts tend to be slightly overestimated (<Δz> = 0.45 ± 0.11), suggesting that current templates do not fully describe the spectra of very-high-z sources. Overall, the spectroscopy solidifies photometric redshift evidence for a high spatial density of bright galaxies at z > 8 compared to theoretical model predictions, and further disfavors an accelerated decline in the integrated UV luminosity density at z > 8.
Volume
951
Issue
1
Start page
L22
Issn Identifier
2041-8205
Ads BibCode
2023ApJ...951L..22A
Rights
open.access
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