Speaker: Dr. Yusuke ASO （Korea Astronomy and Space Science Institute）

Place: Zoom

information: Meeting ID: 822 8287 7472 , Passcode: astroPKU , Link: https://us02web.zoom.us/j/82282877472?pwd=VXFOYmtaRUhZMVplYWp1OFQ4OGsvQT09

Time: Monday, December 13, 2021 – 1:30PM

Abstract:

Polarization observations are a current trend of the Atacama Large Millimeter/submillimeter Array (ALMA), which trace magnetic fields or other phenomena around protostars. My previous ALMA observations suggested that magnetic fields with a strength of ~2 mG could result in an infall motion at ~30% of the free fall velocity in the envelope of the Class I protostellar system TMC-1A. To verify this strength, we observed TMC-1A in polarized continuum emission at 1.3 mm using the Submillimeter Array (SMA) and ALMA at ~400 and ~40 au resolutions, respectively. We verified the mG strength by applying the Davis-Chandrasekhar-Fermi method to the SMA result. The ALMA observations detected polarized emission in the central 100-au region and in the outflow direction (north and south). The central component shows polarization directions in the disk-minor axis over ~100 au, suggesting self-scattering on the disk. The northern and southern components also show the polarization direction in the disk-minor direction, which can be explained by toroidal magnetic fields.

Biography: 

Yusuke Aso got his bachelor, master and PhD degree from the department of astronomy, the University of Tokyo, staying in NAOJ Mitaka and Subaru Telescope in the master and PhD terms, respectively. After working as a member of East Asian ALMA Regional Center (EA ARC) in Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), he is now working to Korea Astronomy and Space Science Institute (KASI) as an EA ARC member. Yusuke’s interests include kinematics around protostellar disks, envelopes, and outflows.