(Proposal ID) S14A-013

(PI) Nishiyama Shogo

(Proposal Title)
 Gas Cloud Accretion onto the SMBH SgrA* and Formation of Jet 2

(Abstract)
A dense gas cloud is rapidly approaching the Galactic supermassive black hole 
(SMBH) SgrA*, and will be ~ 1,600 Schwarzschild radii from the SMBH at the 
pericenter of its eccentric orbit in Mar 2014 (updated). The cloud is expected 
to be disrupted by instabilities and tidal forces, and cloud fragments accrete 
onto the SMBH on dynamical timescales of several weeks to several months, 
suggesting a jet formation in 2014. So we are carrying out daily monitoring 
observations of SgrA* 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 
VERA 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.