摘要
We have performed a dense core survey toward the Infrared Dark Cloud G14.225-0.506 at 3 mm continuum emission with the Atacama Large Millimeter/Submillimeter Array (ALMA). This survey covers the two hub-filament systems with an angular resolution of (∼0.03 pc). We identified 48 dense cores. 20 out of the 48 cores are protostellar due to their association with young stellar objects (YSOs) and/or X-ray point-sources, while the other 28 cores are likely prestellar and unrelated with known IR or X-ray emission. Using APEX 870 μm continuum emission, we also identified the 18 clumps hosting these cores. Through virial analysis using the ALMA N 2 H + and VLA/Effelsberg NH 3 molecular line data, we found a decreasing trend in the virial parameter with decreasing scales from filaments to clumps, and then to cores. The virial parameters of 0.1-1.3 in cores indicate that cores are likely undergoing dynamical collapse. The cumulative core mass function for the prestellar core candidates has a power law index of α=1.6,with masses ranging from 1.5 to 22 Ṁ. We find no massive prestellar or protostellar cores. Previous studies suggest that massive O-type stars have not been produced yet in this region. Therefore, high-mass stars should be formed in the prestellar cores by accreting a significant amount of gas from the surrounding medium. Another possibility is that low-mass YSOs become massive by accreting from their parent cores that are fed by filaments. These two possibilities might be consistent with the scenario of global hierarchical collapse.