SHINING I. Survey observational trends

These galaxies include star-forming, active-galactic nuclei (AGNs), and luminous infrared galaxies (LIRGs). We find an increasing number of galaxies (and kiloparsec-size regions within galaxies) with low line-to-FIR continuum ratios as a function of increasing FIR luminosity (LFIR), dust infrared color, LFIR to molecular gas mass ratio (LFIR/Mmol), and FIR surface brightness ({Sigma}FIR).

The correlations between the [CII]/FIR or [OI]/FIR ratios with {Sigma}FIR are remarkably tight (~0.3dex scatter over almost four orders of magnitude in {Sigma}FIR). We observe that galaxies with L_FIR_/M_mol_>~80L_{sun}_/M_{sun}_ and {Sigma}FIR>~10^11^L_{sun}_/kpc^2^ tend to have weak fine-structure line-to-FIR continuum ratios, and that LIRGs with infrared sizes >~1kpc have line-to-FIR ratios comparable to those observed in typical star-forming galaxies.