(Proposal ID) S15A-009

(PI) Nishiyama, Shogo

(Proposal Title)
 Gas Cloud Accretion onto the SMBH SgrA* and Formation of Jet 4

(Abstract)
A dense gas cloud was detected to be rapidly approaching the Galactic 
supermassive black hole (SMBH) Sgr A*, and was ~1,600 Schwarzschild radii from 
the SMBH at the pericenter of its eccentric orbit in Mar 2014. Ongoing tidal 
disruption has been observed, and cloud fragments are expected to accrete onto 
the SMBH on dynamical timescales, suggesting a jet formation in the following 
years. So we are carrying out daily monitoring observations of Sgr A* in near-
infrared and radio wavelengths, and we propose quick follow-up observations 
with Subaru/Gemini. Br-gamma line emission maps obtained with Gemini/NIFS will 
be used to fine tune our 3D simulation to estimate how much mass accretes, and 
when the fragments accrete onto the SMBH. Polarimetric and astrometric signals 
from a jet taken with Subaru/HiCIAO and KaVA will be compared with the finely 
tuned simulation to understand the timescale of jet formation, and to 
investigate the correlation between the accreted mass of the cloud fragments 
and a luminosity of the newly-formed jet. Spectroscopic and imaging 
observations from 1.6 - 11 mum (Subaru/IRCS, COMICS) will also be conducted 
to understand processes responsible for near to mid-infrared emission during 
the accretion event.