ALMA Observation of a z ≳ 10 Galaxy Candidate Discovered with JWST

We report the observation by the Atacama Large Millimeter/submillimeter Array (ALMA) of a z greater than or similar to 10 galaxy candidate (GHZ1) discovered from the GLASS-JWST Early Release Science Program. Our ALMA program aims to detect the [O III] emission line at the rest-frame frequency 3393.0062 GHz (88.36 mu m) and far-IR continuum emission with the spectral window setup seamlessly covering a 26.125 GHz frequency range (10.10 < z < 11.14). A total of 7 hr of on-source integration was employed, using four frequency settings to cover the full range (1.7 hr per setting), with 0 ''.7 angular resolution. No line or continuum is clearly detected, with 5 sigma upper limits on the line emission of 0.93 mJy beam(-1) at 25 km s(-1) channel(-1) and on the continuum emission of 30 mu Jy beam(-1). We report marginal spectral (at 225 km s(-1) resolution) and continuum features (4.1 sigma and 2.6 sigma peak signal-to-noise ratio, respectively), within 0 ''.17 from the JWST position of GHZ1. This spectral feature implies z = 10.38 and needs to be verified with further observations. Assuming that the best estimate of photometric redshift (z = 10.60(-0.60)(+0.52)) is correct, the model of the galaxy's broadband spectral energy distribution for the 3 sigma upper limit of the continuum flux from GHZ1 suggests that GHZ1 has a small amount of dust (M-d less than or similar to 10(4) M-circle dot) at a high temperature (T-d greater than or similar to 90 K). The 5 sigma upper limit on the [O III](88 mu m) line luminosity and the inferred star formation rate of GHZ1 are consistent with the properties of low-metallicity dwarf galaxies. We also report serendipitous clear detections of six continuum sources at the locations of the JWST galaxy counterparts in the field.

Automated summary

This study reports the discovery of a high redshift (z greater than or similar to 10) galaxy candidate (GHZ1) through observations by ALMA. The analysis reveals the presence of a marginal spectral feature and continuum features, suggesting a redshift of z = 10.38. The broadband spectral energy distribution of GHZ1 indicates the presence of a small amount of high-temperature dust, consistent with the properties of low-metallicity dwarf galaxies. Additionally, six continuum sources were serendipitously detected at the locations of JWST galaxy counterparts in the field.