JWST-ALMA Study of a Hub-Filament System in the Nascent Phase

Abstract

Star clusters, including high-mass stars, form within hub-filament systems (HFSs). Observations of HFSs that remain unaffected by feedback from embedded stars are rare yet crucial for understanding the mass inflow process in high-mass star formation. Using the JWST NIRCAM images, Dewangan et al. 2024, reported that the high-mass protostar G11P1 is embedded in a candidate HFS (G11P1-HFS; $<0.6$ pc). Utilizing ALMA N${}_2$H${}^{+}$(1-0) data, we confirm the presence of G11P1-HFS and study the dense gas kinematics. We analyzed the position-position-velocity (PPV) map and estimated on-sky velocity gradient ($V_g$) and gravity (${\mathcal{F}}_g$) vectors. The spatial distribution of gas velocity and H${}_2$ column density was examined. The steep $V_g$ of 5 km s${}^{-1}$ pc${}^{-1}$ and $-$7 km s${}^{-1}$ pc${}^{-1}$ toward either side of G11P1-hub, and the decreasing $V_g$ toward the hub, identify G11P1-HFS as a small-scale HFS in its nascent phase. $V_g$ and ${\mathcal{F}}_g$ align along the filaments, indicating gravity-driven flows. This work highlights the wiggled, funnel-shaped morphology of a HFS in PPV space, suggesting the importance of subfilaments or transverse gas flows in mass transportation to the hub.

10 pages, 11 figures, 1 table, Accepted for publication in A&A Letters