TY - JOUR
T1 - Early Results from GLASS-JWST. XIV. A Spectroscopically Confirmed Protocluster 650 Million Years after the Big Bang
AU - Morishita, Takahiro
AU - Roberts-Borsani, Guido
AU - Treu, Tommaso
AU - Brammer, Gabriel
AU - Mason, Charlotte A.
AU - Trenti, Michele
AU - Vulcani, Benedetta
AU - Wang, Xin
AU - Acebron, Ana
AU - Bahé, Yannick
AU - Bergamini, Pietro
AU - Boyett, Kristan
AU - Bradac, Marusa
AU - Calabrò, Antonello
AU - Castellano, Marco
AU - Chen, Wenlei
AU - De Lucia, Gabriella
AU - Filippenko, Alexei V.
AU - Fontana, Adriano
AU - Glazebrook, Karl
AU - Grillo, Claudio
AU - Henry, Alaina
AU - Jones, Tucker
AU - Kelly, Patrick L.
AU - Koekemoer, Anton M.
AU - Leethochawalit, Nicha
AU - Lu, Ting Yi
AU - Marchesini, Danilo
AU - Mascia, Sara
AU - Mercurio, Amata
AU - Merlin, Emiliano
AU - Metha, Benjamin
AU - Nanayakkara, Themiya
AU - Nonino, Mario
AU - Paris, Diego
AU - Pentericci, Laura
AU - Rosati, Piero
AU - Santini, Paola
AU - Strait, Victoria
AU - Vanzella, Eros
AU - Windhorst, Rogier A.
AU - Xie, Lizhi
N1 - Funding Information:
We thank Richard Ellis and Nicolas Laporte for useful conversations on the interpretation of the spectroscopic redshift of YD4. We thank the anonymous referee for their careful reading of the manuscript and constructive comments. Support for program JWST-ERS-1324 and HST-GO-17231.015-A was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. The specific observations analyzed can be accessed via 10.17909/bwwe-4a42 . K.G. acknowledges support from Australian Research Council Laureate Fellowship FL180100060. C.M. and T.Y.L. acknowledge support by the VILLUM FONDEN under grant 37459. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. This research is supported in part by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. We acknowledges support from the INAF Large grant 2022 “Extragalactic Surveys with JWST” (PI Pentericci). We acknowledge financial support from grants PRIN-MIUR 2017WSCC32 and 2020SKSTHZ. P.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238. Y.M.B. gratefully acknowledges funding from the Dutch Science Organisation (NWO) under Veni grant No. 639.041.751. A.V.F. is grateful for financial support from the Christopher R. Redlich Fund and many individual donors. B.M. acknowledges support from Australian Government Research Training Program (RTP) Scholarships and the Jean E Laby Foundation. X.W. is supported by the Chinese Academy of Sciences (CAS) Project for Young Scientists in Basic Research, grant No. YSBR-062. R.A.W. acknowledges support from NASA JWST Interdisciplinary Scientist grants NAG5-12460, NNX14AN10G, and 80NSSC18K0200 from GSFC.
Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/4/1
Y1 - 2023/4/1
N2 - We present the spectroscopic confirmation of a protocluster at z = 7.88 behind the galaxy cluster Abell 2744 (hereafter A2744-z7p9OD). Using JWST NIRSpec, we find seven galaxies within a projected radius of 60 kpc. Although the galaxies reside in an overdensity around ≳20× greater than a random volume, they do not show strong Lyα emission. We place 2σ upper limits on the rest-frame equivalent width <16-28 Å. Based on the tight upper limits to the Lyα emission, we constrain the volume-averaged neutral fraction of hydrogen in the intergalactic medium to be x HI > 0.45 (68% C i). Using an empirical M UV-M halo relation for individual galaxies, we estimate that the total halo mass of the system is ≳4 × 1011 M ⊙. Likewise, the line-of-sight velocity dispersion is estimated to be 1100 ± 200 km s−1. Using an empirical relation, we estimate the present-day halo mass of A2744-z7p9OD to be ∼2 × 1015 M ⊙, comparable to the Coma cluster. A2744-z7p9OD is the highest redshift spectroscopically confirmed protocluster to date, demonstrating the power of JWST to investigate the connection between dark-matter halo assembly and galaxy formation at very early times with medium-deep observations at <20 hr total exposure time. Follow-up spectroscopy of the remaining photometric candidates of the overdensity will further refine the features of this system and help characterize the role of such overdensities in cosmic reionization.
AB - We present the spectroscopic confirmation of a protocluster at z = 7.88 behind the galaxy cluster Abell 2744 (hereafter A2744-z7p9OD). Using JWST NIRSpec, we find seven galaxies within a projected radius of 60 kpc. Although the galaxies reside in an overdensity around ≳20× greater than a random volume, they do not show strong Lyα emission. We place 2σ upper limits on the rest-frame equivalent width <16-28 Å. Based on the tight upper limits to the Lyα emission, we constrain the volume-averaged neutral fraction of hydrogen in the intergalactic medium to be x HI > 0.45 (68% C i). Using an empirical M UV-M halo relation for individual galaxies, we estimate that the total halo mass of the system is ≳4 × 1011 M ⊙. Likewise, the line-of-sight velocity dispersion is estimated to be 1100 ± 200 km s−1. Using an empirical relation, we estimate the present-day halo mass of A2744-z7p9OD to be ∼2 × 1015 M ⊙, comparable to the Coma cluster. A2744-z7p9OD is the highest redshift spectroscopically confirmed protocluster to date, demonstrating the power of JWST to investigate the connection between dark-matter halo assembly and galaxy formation at very early times with medium-deep observations at <20 hr total exposure time. Follow-up spectroscopy of the remaining photometric candidates of the overdensity will further refine the features of this system and help characterize the role of such overdensities in cosmic reionization.
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U2 - 10.3847/2041-8213/acb99e
DO - 10.3847/2041-8213/acb99e
M3 - Article
AN - SCOPUS:85153797650
SN - 2041-8205
VL - 947
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L24
ER -