Year: 2023
Type: article
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 ≃ 0.15 − 0.1 + 0.3 ); and at least one of them has a high stellar mass for a galaxy at that redshift ( log ( M ⋆ / M ⊙ ) ≃ 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.
Authors: Pablo Arrabal Haro, Mark Dickinson, Steven L. Finkelstein, Seiji Fujimoto, Vital Fernández, Jeyhan S. Kartaltepe, Intae Jung, Justin W. Cole, Denis Burgarella, Katherine Chworowsky, Taylor A. Hutchison, Alexa M. Morales, Casey Papovich, Raymond C. Simons, Ricardo O. Amorín, Bren E. Backhaus, Micaela B. Bagley, Laura Bisigello, Antonello Calabrò, Marco Castellano, Nikko J. Cleri, Romeel Davé, Avishai Dekel, Henry C. Ferguson, Adriano Fontana, Eric Gawiser, Mauro Giavalisco, Santosh Harish, Nimish P. Hathi, Michaela Hirschmann, Benne W. Holwerda, Anton M. Koekemoer, Rebecca L. Larson, Ray A. Lucas, Bahram Mobasher, Pablo G. Pérez-González, Nor Pirzkal, Caitlin Rose, Paola Santini, Jonathan R. Trump, Alexander de la Vega, Xin Wang, Benjamin J. Weiner, Stephen M. Wilkins, Guang Yang, L. Y. Aaron Yung, Jorge A. Zavala
Institutions: NSF NOIRLab, The University of Texas at Austin, University of La Serena, Rochester Institute of Technology, Space Telescope Science Institute, Texas A&M University, Centre National de la Recherche Scientifique, Aix-Marseille Université, Goddard Space Flight Center, University of Connecticut, University of Padua, Osservatorio Astronomico di Padova, Astronomical Observatory of Rome, National Institute for Astrophysics, University of the Western Cape, University of Edinburgh, Hebrew University of Jerusalem, Rutgers, The State University of New Jersey, University of Massachusetts Amherst, École Polytechnique Fédérale de Lausanne, University of Louisville, Universidad de La Laguna, Université Paris Cité, Université Paris Sciences et Lettres, Observatoire de Paris, Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères, Instituto de Astrofísica de Canarias, University of California, Riverside, Centro de Astrobiología, Chinese Academy of Sciences, Beijing Normal University, National Astronomical Observatories, University of Chinese Academy of Sciences, University of Arizona, University of Sussex, University of Malta, University of Groningen, Space Research Organisation Netherlands, National Astronomical Observatory of Japan
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
OpenAlex ID: W4383375050