An upper limit on [O III] 88 ?m and 1.2 mm continuum emission from a JWST<i>z</i> ? 12–13 galaxy candidate with ALMA

A number of new $z>11$ galaxy candidates have recently been identified based on public James Webb Space Telescope (JWST) NIRCam observations. Spectroscopic confirmation these is necessary to robustly measure their redshift and put them in the context our understanding buildup galaxies early Universe. GLASS-z13 one candidates, with a reported photometric $z>11.9$. I present publicly available Atacama Large Millimeter/submillimeter Array (ALMA) band 6 Director's Discretionary Time observations (project 2021.A.00020.S; PI T. Bakx), taken acquire spectroscopic for by searching [OIII] line emission range $z=11.9-13.5$. No detected integrated spectra extracted within an aperture around GLASS-z13, nor when using automated finding algorithm (applying different uv-weighting strategies imaging). 1.2 mm continuum associated not either. If at z$\approx$12-13, this implies 3-$\sigma$ upper limit rest-frame $\sim$90 $\mu$m $\sim1\times10^8\,\rm{L}_\odot$ 10.8 $\mu$Jy, respectively. The non-detection does necessarily imply that $z\approx12-13$. It can also be explained low metallicity ($\sim 0.2\,\rm{Z}_\odot$ or lower) and/or high-density (at least 100 $\rm{cm}^{-3}$) interstellar medium. This work demonstrates synergy between ALMA JWST study properties first galaxies, although JWST/NIRSpec spectroscopy will confirm reject high photometric-redshift GLASS-z13.