An ALMA Study of the Massive Molecular Clump N159W-North in the Large Magellanic Cloud: A Possible Gas Flow Penetrating One of the Most Massive Protocluster Systems in the Local Group

Massive dense clumps in the Large Magellanic Cloud can be an important laboratory to explore the formation of populous clusters. We report multiscale ALMA observations of the N159W-North clump, which is the most CO-intense region in the galaxy. High-resolution CO isotope and 1.3 mm continuum observations with an angular resolution of similar to 0.'' 25 (similar to 0.07 pc) revealed more than five protostellar sources with CO outflows within the main ridge clump. One of the thermal continuum sources, MMS-2, shows an especially massive/dense nature whose total H-2 mass and peak column density are similar to 10(4) M (circle dot) and similar to 10(24) cm(-2), respectively, and harbors massive (similar to 100 M (circle dot)) starless core candidates identified as its internal substructures. The main ridge containing this source can be categorized as one of the most massive protocluster systems in the Local Group. The CO high-resolution observations found several distinct filamentary clouds extending southward from the star-forming spots. The CO (1-0) data set with a larger field of view reveals a conical, similar to 30 pc long complex extending toward the northern direction. These features indicate that a large-scale gas compression event may have produced the massive star-forming complex. Based on the striking similarity between the N159W-North complex and the other two previously reported high-mass star-forming clouds in the nearby regions, we propose a teardrops inflow model that explains the synchronized, extreme star formation across >50 pc, including one of the most massive protocluster clumps in the Local Group.

Automated summary

Massive dense clumps in the Large Magellanic Cloud can serve as an important laboratory for studying the formation of populous clusters. The N159W-North clump is found to be the most CO-intense region in the galaxy, with several protostellar sources and CO outflows. One particularly massive and dense protostellar source, MMS-2, is identified and found to contain massive starless core candidates. The observations also reveal filamentary clouds and a large-scale gas compression event that may have contributed to the formation of the star-forming complex.