Oral Presentation

Witnessing Star Cluster Formation in the Central Molecular Zone

Author(s): Xing Lu (NAOJ)

Presenter: Xing Lu (National Astronomical Observatory of Japan)

How massive (>10^4 Msun) star clusters toward the Galactic Center such as the Arches and the Quintuplet are formed is unclear. To address this question, we use ALMA to investigate gas and star formation at 0.01 pc resolution in four massive clouds in the Central Molecular Zone. Although the clouds have similar gas mass and turbulence strength at the large scale, they present very different substructures at the 0.01 pc scale, from virtually no fragmentation to hundreds of fragments (or condensations). The mass of the condensations ranges from <1 Msun to >100 Msun. In addition, signatures of protostellar outflows and hot molecular cores are detected toward many of the condensations. We suggest that three of the clouds are forming clusters consisting of both high-mass (>8 Msun) and low-mass (<2 Msun) stars, and will likely give rise to clusters of 10^2-10^3 Msun. However, none of the four clouds seem to be able to form Arches/Quintuplet-like clusters, which may be able to emerge only in regions like Sgr B2 or by further collapse/merging of protoclusters.