부산대학교 도서관

We exploit moderately resolved [O |$\scriptstyle \rm III$| ], [C |$\scriptstyle \rm II$| ] 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 (κ s ) on |$\approx \, \rm sub-kpc$| 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 |$\scriptstyle \rm II$| ]and [O |$\scriptstyle \rm III$| ]surface brightness (Σ[CII], Σ[OIII]) and the SFR surface density (ΣSFR) to n , κ s , and Z. All five sources are characterized by a central starbursting region, where the Σgas versus ΣSFR align ≈10 × above the KS relation (κ s ≈ 10). This translates into gas depletion times in the range t dep ≈ 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. [ABSTRACT FROM AUTHOR]