학술논문
Early Results from GLASS-JWST. XIV. A Spectroscopically Confirmed Protocluster 650 Million Years after the Big Bang
Document Type
article
Author
Takahiro Morishita; Guido Roberts-Borsani; Tommaso Treu; Gabriel Brammer; Charlotte A. Mason; Michele Trenti; Benedetta Vulcani; Xin Wang; Ana Acebron; Yannick Bahé; Pietro Bergamini; Kristan Boyett; Marusa Bradac; Antonello Calabrò; Marco Castellano; Wenlei Chen; Gabriella De Lucia; Alexei V. Filippenko; Adriano Fontana; Karl Glazebrook; Claudio Grillo; Alaina Henry; Tucker Jones; Patrick L. Kelly; Anton M. Koekemoer; Nicha Leethochawalit; Ting-Yi Lu; Danilo Marchesini; Sara Mascia; Amata Mercurio; Emiliano Merlin; Benjamin Metha; Themiya Nanayakkara; Mario Nonino; Diego Paris; Laura Pentericci; Piero Rosati; Paola Santini; Victoria Strait; Eros Vanzella; Rogier A. Windhorst; Lizhi Xie
Source
The Astrophysical Journal Letters, Vol 947, Iss 2, p L24 (2023)
Subject
Language
English
ISSN
2041-8213
2041-8205
2041-8205
Abstract
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 Ly α emission. We place 2 σ upper limits on the rest-frame equivalent width 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 × 10 ^11 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 × 10 ^15 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