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Toroidal magnetic field revealed  in the pseudodisk of NGC1333 IRAS 4A 

Shih-Ping Lai (National Tsing Hua University). Collaborators: Tao-Chung Ching (NTHU) Josep Miquel Girart (Institut de Ciències de l'Espai, Spain) Ramprasad Rao (ASIAA). Toroidal magnetic field revealed  in the pseudodisk of NGC1333 IRAS 4A . NGC 1333 IRAS 4A. P.

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Toroidal magnetic field revealed  in the pseudodisk of NGC1333 IRAS 4A 

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  1. Shih-Ping Lai (National Tsing Hua University) Collaborators: Tao-Chung Ching (NTHU) Josep Miquel Girart (Institut de Ciències de l'Espai, Spain) Ramprasad Rao (ASIAA) Toroidal magnetic field revealed in the pseudodisk of NGC1333 IRAS 4A 

  2. NGC 1333 IRAS 4A P Magnetic Field Rules!! B what about small scale structure? Polarization map (left) and magnetic field map (right) from Girart, Rao, & Marrone (2006), Science, 313, 812

  3. subcompact array data ( 2-3” ) • comparable to the spatial scales of 1.3 mm BIMA data • extended array data ( 0.8” ) • does the B field remain hourglass morphology at small scales? • magnetic fields in outflows New SMA OBservations

  4. Combine Visibilities new old Spatial freq in N-S (v) Amplitude new Spatial freq in E-W (u) Spatial freq (sqrt(u^2+v^2))

  5. Results Subcompact + compact + extended array data Girart, Rao, Marrone (2006)

  6. Toroidal Magnetic FielDs in the DisK!! Machida et al.(2008) Subcompact + compact + extended array data Data with spatial frequency greater than 50 kλ

  7. Toroidal Magnetic FielDs in the DisK!! Machida et al.(2008) Subcompact + compact + extended array data Data with spatial frequency greater than 50 kλ Allen, Li, Shu 2003

  8. Density • Plummer 1911; Whiteworth & Ward-Thompson 2001 • Magnetic fields – • Lucas et al. (2004) • poroidal (hourglass) component • toroidal component Empirical MOdel Bφ = a2 z(Br/c2)pExp(-r/c2) /|z|2

  9. Amplitude Spatial freq (sqrt(u^2+v^2))

  10. Density • Plummer 1911; Whiteworth & Ward-Thompson 2001 • Magnetic fields – • Lucas et al. (2004) • poroidal (hourglass) component • toroidal component Empirical MOdel Bφ = a2 z(Br/c2)pExp(-r/c2) /|z|2

  11. Density • Plummer 1911; Whiteworth & Ward-Thompson 2001 • Magnetic fields – • Lucas et al. (2004) • poroidal (hourglass) component • toroidal component Empirical MOdel Bφ = a2 z(Br/c2)pExp(-r/c2) /|z|2

  12. Model predictions Pure Hourglass (Poloidal)

  13. Model predictions Pure Hourglass (Poloidal) Hourglass with inclination angle=54 deg

  14. Model predictions Pure Hourglass Hourglass + Toroidal

  15. Data Model

  16. RoTaTion (C17O) Dust C17O Average Velocity  Magnetic braking in action!!

  17. We present the first map of the toroidal magnetic field structure in a disk around protostars • High quality interferometry data with wide uv-range will help us decouple the magnetic field structure along the line of sight Summary  Magnetic Braking in Action!  ALMA data will be extremely helpful

  18. Theoretical models (Analytical or numerical) • binary • common envelop • pseudo-disk and kaplarian disk • outflows • B field • magnetic braking • Ambipolor diffusion WanTED

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