Spatially resolved Kennicutt-Schmidt relation at z 7 and its connection with the interstellar medium properties

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 (kappa(s)) on approximate to sub-kpc scales in the interstellar medium (ISM) of five bright Lyman Break Galaxies at the Epoch of Reionization (z approximate to 7). To do so, we use GLAM, a state-of-art, physically motivated Bayesian model that links the [C II]and [O III]surface brightness (Sigma([CII]), Sigma([OIII])) and the SFR surface density (Sigma(SFR)) to n, kappa(s), and Z. All five sources are characterized by a central starbursting region, where the Sigma(gas) versus Sigma(SFR) align approximate to 10 x above the KS relation (kappa(s) approximate to 10). This translates into gas depletion times in the range t(dep) approximate to 80 - 250 Myr. The inner starbursting centres are characterized by higher gas density (log (n/cm(-3)) approximate to 2.5-3.0) and higher metallicity (log (Z/Z(circle dot)) approximate to -0.5) than the galaxy outskirts. We derive marginally negative radial metallicity gradients (del log Z approximate to -0.03 +/- 0.07 dex/kpc), and a dust temperature (T-d approximate to 32 - 38 K) that anticorrelates with the gas depletion time.