JWST NIRSpec Spectroscopy of the Remarkable Bright Galaxy GHZ2/GLASS-z12 at Redshift 12.34
Journal article, 2024
We spectroscopically confirm the M UV = −20.5 mag galaxy GHZ2/GLASS-z12 to be at redshift z = 12.34. The source was selected via NIRCam photometry in GLASS-JWST Early Release Science data, providing the first evidence of a surprising abundance of bright galaxies at z ≳ 10. The NIRSpec PRISM spectrum shows detections of N iv, C iv, He ii, O iii, C iii, O ii, and Ne iii lines and the first detection at high redshift of the O iii Bowen fluorescence line at 3133 Å rest frame. The prominent C iv line with rest-frame equivalent width (EW) ≈ 46 Å puts GHZ2 in the category of extreme C iv emitters. GHZ2 displays UV lines with EWs that are only found in active galactic nuclei (AGNs) or composite objects at low/intermediate redshifts. The UV line-intensity ratios are compatible with both AGNs and star formation in a low-metallicity environment, with the low limit on the [Ne iv]/[N iv] ratio favoring a stellar origin of the ionizing photons. We discuss a possible scenario in which the high ionizing output is due to low-metallicity stars forming in a dense environment. We estimate a metallicity ≲0.1 Z/Z ⊙, a high ionization parameter log U > −2, a N/O abundance 4-5 times the solar value, and a subsolar C/O ratio similar to the recently discovered class of nitrogen-enhanced objects. Considering its abundance patterns and the high stellar mass density (104 M ⊙ pc−2), GHZ2 is an ideal formation site for the progenitors of today's globular clusters. The remarkable brightness of GHZ2 makes it a “Rosetta stone” for understanding the physics of galaxy formation within just 360 Myr after the Big Bang.
Author
M. Castellano
Osservatorio Astronomico di Roma
Lorenzo Napolitano
Sapienza University of Rome
Osservatorio Astronomico di Roma
A. Fontana
Osservatorio Astronomico di Roma
Guido Roberts-Borsani
University of Geneva
Tommaso Treu
University of California
Eros Vanzella
Istituto nazionale di astrofisica (INAF)
J. A. Zavala
National Astronomical Observatory of Japan
Pablo Arrabal Haro
NSF's National Optical-Infrared Astronomy Research Laboratory (NOIRLab)
Antonello Calabrò
Osservatorio Astronomico di Roma
Mario Llerena
Osservatorio Astronomico di Roma
Sara Mascia
Osservatorio Astronomico di Roma
E. Merlin
Osservatorio Astronomico di Roma
Diego Paris
Osservatorio Astronomico di Roma
L. Pentericci
Osservatorio Astronomico di Roma
P. Santini
Osservatorio Astronomico di Roma
Tom Bakx
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Pietro Bergamini
University of Milan
Istituto nazionale di astrofisica (INAF)
Guido Cupani
University of Trieste
Osservatorio Astronomico di Trieste
Mark Dickinson
NSF's National Optical-Infrared Astronomy Research Laboratory (NOIRLab)
Alexei V. Filippenko
University of California
Karl Glazebrook
Swinburne University of Technology
Claudio Grillo
Istituto nazionale di astrofisica (INAF)
University of Milan
Patrick L. Kelly
University of Minnesota
M. A. Malkan
University of California
C. A. Mason
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
Takahiro Morishita
California Institute of Technology (Caltech)
Themiya Nanayakkara
Swinburne University of Technology
Piero Rosati
Istituto nazionale di astrofisica (INAF)
University of Ferrara
Eleonora Sani
European Southern Observatory Santiago
Xin Wang
Beijing Normal University
Chinese Academy of Sciences
I. Yoon
National Radio Astronomy Observatory
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 972 2 143Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.3847/1538-4357/ad5f88