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Paper: Shapelets for the MWA
Volume: 512, Astronomical Data Analysis Software and Systems XXV
Page: 257
Authors: Riding, J.L.; Mitchell, D.A.; Webster, R.L.
Abstract: The Murchison Widefield Array (MWA), like other low frequency or recently upgraded radio telescopes, has a large field of view. For the MWA, this means any observation will contain a mix of point-like sources, extended sources and diffuse emission. The variety makes for fascinating science and challenging calibrations and deconvolution. For example, bright extended sources complicate the calibration process by corrupting the visibilities of point-like calibrator sources. These effects are more concerning when a bright extended source exists at the edges of the beam or in its side lobes. There are a number of ways to handle bright extended sources and the method proposed here subtracts a shapelet model of the offending source from the raw uv data. Shapelet models make use of smooth gauss-hermite polynomials to better model extended emission with fewer data points then the traditional clean-component maps. Due to their simple Fourier relation, shapelets can be used in the uv domain. It is this method that the MWA's Real Time System will employ to peel foregrounds from MWA fields in the search for the Epoch of Reionisation signal.
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