Jia-Wei Wang (ASIAA); Patrick Koch (ASIAA); Han-Tsung Lee (NCU); Ya-Wen Tang (ASIAA)
Hub-filament systems (HFSs) are a transition stage connecting parsec-scale filaments and proto-clusters. Understanding the origin of HFSs is crucial to reveal how star formation proceeds from clouds to cores. In this talk, we report our JCMT polarization observations toward the hub-filament system SDC13. At 10-pc scales, the B-field traced by the PLANCK polarization data show a converging pattern with SDC13 located at the converging center. Our POL-2 observations reveal “U-shape” B-field morphology at pc-scale within the clouds surrounding SDC13. These “U-shape” patterns are pointing toward the SDC13 following the 10-pc-scale B-fields converging pattern, likely dragged by the ram pressure of the large-scale flows. In addition, we found that the B-field in SDC13 show a 90-degree turn-off in a long, narrow area, consistent with a shock-compressed layer originated from flow collisions. Our results favor the scenario that SDC13 is originated from the shock compression of 10-pc-scale colliding flows.