CORE high-mass star-forming regions

The column densities of 11 different species are determined by fitting the emission lines with XCLASS. Within the 18 observed regions, we identify 22 individual cores with associated 1.37mm continuum emission and with a radially decreasing temperature profile. We find an average temperature power-law index of q=0.4+/-0.1 and an average density power-law index of p=2.0+/-0.2 on scales on the order of several 1000au.

Comparing these results with values of p derived in the literature suggest that the density profiles remain unchanged from clump to core scales. The column densities relative to N(C18O) between pairs of dense gas tracers show tight correlations. We apply the physical-chemical model MUlti Stage ChemicaL codE (MUSCLE) to the derived column densities of each core and find a mean chemical age of ~60000yrs and an age spread of 20000-100000yrs.

With this paper we release all data products of the CORE project available at mpia.de/core. The CORE sample reveals well constrained density and temperature power-law distributions. Furthermore, we characterize a large variety in molecular richness that can be explained by an age spread confirmed by our physical-chemical modeling.

The hot molecular cores show the most emission lines, but we also find evolved cores at an evolutionary stage, in which most molecules are destroyed and thus the spectra appear line-poor again.