Calibration artefacts in KAT-7 data

In [2] we focused on explaining the ghost pattern that appears during the calibration of a regular east-west array. This paper will concentrate on extending our previous results to a general irregular array layout. In radio interferometry calibration refers to the estimation and correction of instrumental and environmental errors induced onto interferometric data. Ghosts are point-like spurious artefacts that are created when calibrating interferometric data with an incomplete sky model. For a regular east west array (given a two-source scenario) we found that each baseline produces its own unique ghost pattern and that these ghosts always appeared in a straight line. Moreover, we found that the spacing between the the ghosts produced for each baseline were inversely proportional to baseline length. In this, paper we will show that for a general irregular layout, ghosts no longer form in a straight line.