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transientskp / old-aartfaac-imaging-pipeline

AARTFAAC Imaging Pipeline
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Add visibility taper during imaging #5

Closed jdswinbank closed 8 years ago

jdswinbank commented 10 years ago

Peeyush writes:

Due to the large number of short baselines, AARTFAAC sees a lot of extended emission, which is also very bright at LOFAR frequencies. During calibration, this bright diffuse emission is filtered by dropping the shortest baselines. This results in the calibrated visibilities also having a sharp 'hole' in the uv plane center, which in turn leads to ringing in the images. Tapering this hole is seen to help in the ringing in the images, although the calibration seems to be resilient to it.

Further, an external weighting before imaging to compensate for the irregular density of the sampled visibilities may also be needed.