Photometric detection at $7.7\ \mu\mathrm{m}$ of a galaxy beyond redshift $14$ with JWST/MIRI

TL;DR

This paper reports the first photometric detection at 7.7 micrometers of a galaxy beyond redshift 14 using JWST/MIRI, revealing insights into early galaxy formation and starburst activity.

Contribution

It presents the first mid-infrared photometric detection of a galaxy at z > 14, providing new data on stellar populations and emission lines at this epoch.

Findings

Galaxy at z=14.32 detected at 7.7 μm with JWST/MIRI.

At least one-third of flux from rest-optical emission lines.

Galaxy contains about half a billion solar masses in stars.

Abstract

The James Webb Space Telescope (JWST) has spectroscopically confirmed numerous galaxies at $z > 10$. While weak rest-ultraviolet emission lines have only been seen in a handful of sources, the stronger rest-optical emission lines are highly diagnostic and accessible at mid-infrared wavelengths with the Mid-Infrared Instrument (MIRI) of JWST. We report the photometric detection of the distant spectroscopically confirmed galaxy JADES-GS-z14-0 at $z = 14.32^{+0.08}_{-0.20}$ with MIRI at $7.7\ \mu\mathrm{m}$. The most plausible solution for the stellar population properties is that this galaxy contains half a billion solar masses in stars with a strong burst of star formation in the most recent few million years. For this model, at least one-third of the flux at $7.7\ \mu\mathrm{m}$ comes from the rest-optical emission lines $\mathrm{H}\beta$ and/or $\mathrm{[OIII]}\lambda\lambda4959,5007$. The inferred properties of JADES-GS-z14-0 suggest rapid mass assembly and metal enrichment during the earliest phases of galaxy formation. This work demonstrates the unique power of mid-infrared observations in understanding galaxies at the redshift frontier.