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

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

Istituto nazionale di astrofisica (INAF)

University of Milan

Guido Cupani

Osservatorio Astronomico di Trieste

University of Trieste

Mark Dickinson

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 2 143

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.3847/1538-4357/ad5f88

More information

Latest update

9/25/2024