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

Abstract

We report the observation by the Atacama Large Millimeter/submillimeter Array (ALMA) of a z ≳ 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 μ 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 σ 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 μ Jy beam ^−1 . We report marginal spectral (at 225 km s ^−1 resolution) and continuum features (4.1 σ and 2.6 σ 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 σ upper limit of the continuum flux from GHZ1 suggests that GHZ1 has a small amount of dust ( M _d ≲ 10 ^4 M _⊙ ) at a high temperature ( T _d ≳ 90 K). The 5 σ upper limit on the [O iii ] _88 _μ _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.

Keywords

• Galaxy formation
• High-redshift galaxies
• Interstellar medium
• Interstellar dust
• Interferometers
• Submillimeter astronomy