On the diagnostic power of FIR/sub-mm SED fitting in massive galactic molecular clumps

We used FIR and submillimeter continuum data from Herschel and the Atacama PathfinderEXperiment (APEX) to fit pixel-by-pixel modified Planck SEDs to prestellar and protostellar clumps in the Census of High- and Medium-mass Protostars(CHaMP) ($280^{\circ}<\ell<300^{\circ}$, $-4^{\circ} molecular cloud. We also find that $L/M$ traces $T_{\text{d}}$ almost exclusively, and therefore is not an independent star formation tracer, but minima in $T_{\text{d}}$ almost universally coincide with maxima in \ncol, implying that cooling and density enhancement must be simultaneous steps in prestellar clump evolution. Finally, based on generalized histogram N-PDFs of clump-scale (1-5 pc) and cloud-scale ($\gtrsim10$ pc) samples, we could only obtain dual log-normal and power-law fits to $\sim10\%$ of the clumps. The physical parameters derived from these fits approach theoretical expectations, but have largely unknown uncertainties, so we advise treating the results of N-PDF fitting with caution.