The Innermost Mass Distribution of the Gravitational Lens SDP.81 from ALMA Observations
High-resolution Band 7 continuum negative image of SDP.81. This is the highest-resolution submillimeter observation of a strong lensing galaxy to date.
High-resolution Band 7 continuum negative image of SDP.81. The beam size is the black ellipse in the bottom left. Open symbols are the positions used for the lens modeling. Filled symbols are the positions of the corresponding images predicted by our most probable power-law lens model. The small filled symbols near the center are the modeled source positions for the same case. The critical curves (solid blue) and caustics (dashed orange) are overplotted. The image is 4.2′′ on a side.