Visit ASIAA Homepage Registration Deadline: August 15, 2019 (Taiwan Time)
Science with the Submillimeter Array: Present and Future
November 4(Mon)-5(Tue), 2019
ASIAA, Taipei, Taiwan

Poster Presentation

The accretion process of cold molecular gas to the closest supermassive black hole SgrA*

Author(s): Pei-Ying Hsieh (ASIAA); Patrick Koch (ASIAA); Woong-Tae Kim (SNU); Paul Ho (ASIAA/EAO); Ya-Wen Tang (ASIAA); Hsi-Wei Yen (ASIAA); Nanase Harada (ASIAA)

Presenter: Pei-Ying Hsieh (ASIAA)

Dynamics of streamers towards the CND - witnessed on-going mass accretion
The interaction between a supermassive black hole (SMBH) and the surrounding material is of primary importance in astrophysics. The detection of the molecular 2-pc circumnuclear disk (CND) immediately around the Milky Way SMBH, SgrA*, resembles the "molecular torus" in extragalactic nuclei, provides an unique opportunity to study SMBH accretion at sub-parsec scales. However, the CND is transient if its gas density is under the tidal threshold of SgrA*/nuclear star clusters, thus depleting the source of fuel. In our new CS line maps, we find several dense gas streamers appear to carry gas directly toward the nuclear region and might be captured by the central potential. These streamers show a signature of “infalling” motion with progressively higher velocities as the gas approaches the CND and finally end up co-rotating with the CND. Furthermore, utilizing the 850 um polarization data, we also find that the magnetic field appears dynamically significant toward the CND and also onwards to the inward ionized flows. Our results might suggest a possible mechanism of gas feeding to the CND. In this conference, I will also discuss the observed morphology, kinematics of gas, and effects of magnetic fields in the GC. I will also present our newest ALMA CS line maps in this region. As the nearest observable Galactic nucleus, this feeding process may have implications for understanding the processes in extragalactic nuclei.

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