The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). IX. Physical Properties and Spatial Distribution of Cores in IRDCs

Abstract The initial conditions found in infrared dark clouds (IRDCs) provide insights on how high-mass stars and stellar clusters form. We have conducted high-angular resolution high-sensitivity observations toward thirty-nine massive IRDC clumps, which been mosaicked using the 12 7 m arrays from Atacama Large Millimeter/submillimeter Array. targets are 70 μ (220–4900 M ⊙ ), dense (>10 4 cm −3 cold (∼10–20 K) clumps located at distances between 2 6 kpc. identify an unprecedented number of 839 cores, with masses 0.05 81 1.3 mm dust continuum emission. About 55% cores low-mass (<1 whereas ≲1% (7/839) (≳27 ). detect no prestellar cores. most (MMC) identified within individual lack sufficient mass to form without additional feeding. find that MMCs is correlated clump surface density, implying denser produce more There significant segregation except for a few tentative detections. In contrast, show once density considered instead mass. Although emission resolves network filaments, some consist hub-filament systems, majority not hubs. Our analysis shows preferred location respect earliest stages star formation.