Time Coordinate: 3:30 pm 12th May 2017 (Friday)

Space Coordinate: NTHU General Building II, R521

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Speaker A: Pou-Ieng Cheong (NTHU)

Title: ALMA Observations of Spiral Accretion Flows Towards Extremely Young Protostars

Abstract:

Studying the accretion flows toward extremely young protostars is an important step for understanding how the protostars and the protoplanetary disks are assembled in the early stage of star formation. The accretion flows are commonly seen in the MHD numerical simulations; however, it is rarely observed toward young protostars. Here we present our ALMA observations of the accretion flows around the extremely young protostar VLA1623A with a Keplerian disk likely just formed (Murillo, Lai, et al. 2013). "Dendrogram" algorithm (Goodman et al. 2009) are used to identify the accretion flows, and we find the three brightest "branches" and their associated "leaves" likely correspond to the spiral structure flowing toward the central young cluster. We further compare the three accretion flows in the position-position-velocity cube to the CMU model (Ulrich 1976; Cassen & Moosman 1981) which describe the velocity structure of the gas accreting to the central protostar with constant angular momentum. We find that our identified branch structures well match with the CMU model.

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Speaker B: Li-Wen Liao (NTHU)

Title: Anatomy of the internal bow shocks in protostellar jet