ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions— III. Catalogues of candidate hot molecular cores and Hyper/Ultra compact HII regions

We have identified 453 compact dense cores in 3mm continuum emission maps in the ATOMS (ALMA Three-millimeter Observations of Massive Star-forming regions) survey, and compiled three catalogues of high-mass star forming cores. One catalogue, refereed to as H/UC-HII catalogue, includes 89 cores that enshroud hyper/ultra compact (H/UC) HII regions as characterized by associated compact H40 emission. A second catalogue, referred to as pure s-cHMC, includes 32 candidate Hot Molecular Cores (HMCs) showing a rich spectrum (N > 20 lines) of complex organic molecules (COMs) but not associated with H/UC HII regions. The third catalogue, referred to as pure w-cHMC, includes 58 candidate HMCs with relatively low levels of COM richness and not associated with H/UC HII regions. These three catalogues of dense cores provide an important foundation for future studies of the early stages of high mass star formation across the Milky Way. We find that nearly half of H/UC-HII cores are candidate HMCs. From the number counts of COM-containing and H/UC-HII cores, we suggest that the duration of high-mass protostellar cores (or candidate HMCs) showing chemically rich features is at least comparable to the lifetime of H/UC-HII regions. For cores in the H/UC-HII catalogue, the width of the H40 line increases as the core size decreases, suggesting that the non-thermal (e.g., dynamical and pressure) line-broadening mechanisms dominate on the smaller scales of the H/UC-HII cores.