A theoretical investigation of far-infrared fine structure lines at z > 6 and of the origin of the [O III ] 88 μm/[C II ] 158 μmenhancement
The far-infrared (FIR) fine structure lines [C II]158 μm, [O III]88 μm, [N II]122 μm, and [N III]57 μm are excellent tools for probing the physical conditions of the interstellar medium (ISM). The [O III]88 μm/[C II]158 μm and [O III]88 μm/[N II]122 μm luminosity ratios have shown to be promising tracers of the ionisation state and gas-phase metallicity of the ISM. Observations of galaxies at reds
