A. Young, S.J. Wijnholds, T.D. Carozzi, R. Maaskant, M.V. Ivashina and D. Davidson, "Efficient correction for both direction-dependent and baseline-dependent effects in interferometric imaging: An A-stacking framework," Astronomy & Astrophysics, V577, no. A56, pp1-11, May 2015.
A general framework is presented for modeling direction-dependent effects that are also baseline-dependent, as part of the calibration and imaging process. Within this framework such effects are represented as a parametric linear model in which basis functions account for direction dependence, whereas expansion coefficients account for the baseline dependence. This separation enables the use of a multiple fast Fourier transform-based implementation of the forward calculation (sky to visibility) in a manner similar to the W-stacking solution for non-coplanar baselines, and offers a potential improvement in computational efficiency in scenarios where the gridding operation in a convolution-based approach to direction-dependent effects may be too costly. Two novel imaging approaches that are possible within this framework are also presented.
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