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ABSTRACT We exploit moderately resolved O III, C II and dust continuum ALMA observations to derive the gas density (n), the gas-phase metallicity (Z), and the deviation from the Kennicutt–Schmidt (KS) relation (κs) on \, sub-kpc scales in the interstellar medium (ISM) of five bright Lyman Break Galaxies at the Epoch of Reionization (z ≈ 7). To do so, we use GLAM, a state-of-art, physically motivated Bayesian model that links the C IIand O IIIsurface brightness (ΣCII, ΣOIII) and the SFR surface density (ΣSFR) to n, κs, and Z. All five sources are characterized by a central starbursting region, where the Σgas versus ΣSFR align ≈10 × above the KS relation (κs ≈ 10). This translates into gas depletion times in the range tdep ≈ 80 − 250 Myr. The inner starbursting centres are characterized by higher gas density (log (n/cm−3) ≈ 2. 5–3. 0) and higher metallicity (log (Z/Z⊙) ≈ −0. 5) than the galaxy outskirts. We derive marginally negative radial metallicity gradients (∇log Z ≈ −0. 03 ± 0. 07 dex/kpc), and a dust temperature (Td ≈ 32 − 38 K) that anticorrelates with the gas depletion time.
Vallini et al. (Sat,) studied this question.