ALMA Strawperson Donut/Double-Ring C Array

Physical Descriptions:

  1. Maximum baseline 680 m
  2. Minimum baseline 15 m
  3. Maximum near-in sidelobes are about 5%.
  4. The outer sidelobes are strongly suppressed by earth rotation synthesis (less than 5%).

Pad Positions:

Pad positions are given here in meters. The X and Y positions are with respect to a reference position on the 5 degree mask. To convert to SAM56 coordintes:

SAM56 E = 624820 + X

SAM56 N = 7449700 + Y

Array Layout, UV Distribution, Synthesized Beam:



(Upper left panel) Pad distribution shown with the "5 degree slope" mask in red. (Upper right panel) Snapshot UV distribution and pad postions from CONFI. (Lower left panel) Snapshot dirty beam. The plotted color ranges between -5% (blue) and +10% (red). Maximum near-in sidelobe 5.2% and the largest sidelobe inside the PB is about 15%. (Lower right panel) Radial density distribution of the visibility points for a snapshot observation. Only 5% of the UV cells are sampled.

UV Distribution, Synthesized Beam (90 minute synthesis):


(Left panel) A dirty beam after a 90 minutue long earth rotation synthesis. The plotted color ranges between -5% (blue) and +10% (red). While the near-in sidelobes remain more or less the same (5.2%) as the snapshot case (above), the outer sidelobes are strongly suppressed by earth rotation synthesis (less than 5%). (Right panel) Radial density distribution of the visibility points. About 45% of the UV cells are sampled after 90 minutes of observations.