ALMA View of the Circum-nuclear Disk of the Galactic Center; Tidally-disrupted Molecular Clouds falling to the Galactic Center

Understand

We present the high angular resolution and high sensitivity images of the "Circum-Nuclear Disk (CND)" and its surrounding region of Milky Way Galaxy in the CS J=2-1, SiO v=0 J=2-1, H^13CO^+ J=1-0, C^34S J=2-1, and CH_3OH J_{K_a, K_c}=2_{1,1}-1_{1,0}A_{--} emission lines using ALMA.

• The CND is recognized as a torus-like molecular gas with gaps in these emission lines except for the CH_3OH emission line.
• The inner and outer radii of the CND are estimated to be R_in~1.5 and R_out~2 pc, respectively.
• The velocities of the rotation and radial motion are estimated to be V_rot~115 km s^-1 and V_rad~23 km s^-1, respectively.