Oral Presentation

Multi-scale magnetic field and fragmentation of IRDC SDC18.624-0.070

Author(s): Han-Tsung Lee (ASIAA & NTU), Ya-Wen Tang (ASIAA), Jia-Wei Wang (ASIAA), Patrick Koch (ASIAA), Seamus Clarke (ASIAA)

Presenter: Han-Tsung Lee (ASIAA & NTU)

We investigate the evolution of magnetic field from 1 pc filament scale to 0.01 pc core scale
in filamentary infrared dark cloud SDC18.624-0.070 and its two clumps SDC18-N and SDC18-S
using dust polarization observations of three different resolutions from JCMT and SMA. We
found magnetic field preserves its mean orientation with less than 10 deg variation while
displays increasing angle dispersion from filament to core scale. The magnetic field is also
perpendicular to major axes of structures at all scales(filament, clumps and cores),suggesting
it is dynamically important in regulating material collapse. Multi-scale estimate of
gravitational energy density, magnetic pressure, and turbulent pressure shows the relative
importance of gravity, magnetic field, and turbulence in clumps affects fragmentation
morphology in SDC18.624-0.070, in which higher magnetization leads to lower level of
fragmentation, while opposite trend is reported in another IRDC G34.43+00.24. Finally, we
discuss the possible application of ALMA for future follow-up observations.