Jia-Wei Wang (NTHU); Shih-Ping Lai (NTHU); BISTRO collabration
Hub-filament systems are one of the commonly seen filamentary structures, composed of a dense central hub with several filaments converging to the hub, and are the potential site of cluster formation. As part of BISTRO survey, we mapped the magnetic field within a hub-filament system in IC5146 cloud complex using JCMT 850 micron polarization. The results show that the magnetic fields within the hub-filament system are mostly inherited from large scale uniform magnetic fields, but also dragged by the gravitational contraction of the large scale main filament. We further found that the clumps within the hub-filament system is aligned with the local magnetic fields. To explain the observed feature, we propose a scenario that the hub-filament system is formed via the fragmentation of lager scale filament.