Difference imaging and multi-channel Clean

Talk at the imaging and calibration workshop Algorithms2008 in Oxford, 3 December 2008

O. Wucknitz [1]

  1. Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany

Abstract

I discuss the development of a difference imaging algorithm in radio interferometry. Independent deconvolution with subsequent subtraction is not an option, because difference images produced in this way would be dominated by deconvolution errors. A multi-channel adaption of CLEAN is a viable alternative. Similar approaches are needed for wide-band imaging, where it is not variability with time but with frequency that has to be taken into account. All these methods (plus multi-scale Clean) can be described in a general formalism. This multi-channel Clean algorithm builds a model consisting of several channels (corresponding to expansions in time, frequency or resolution) and uses the standard Clean approach to find an optimised solution for the generalised deconvolution problem.

A previous version (with some additional lensing material) was presented as a Bonn lunch colloquium.

My other presentation at this workshop can be found here.



download original presentation
PDF file (1.6 MB, last change 2 Dec 2008)
30 pages, suitable for presentation with acroread. This version also includes some hyperlinks for quick navigation and links to references.

download printable version (small)
PDF file (802.4 kB, last change 2 Dec 2008)
Paper saving version. 4 pages, text mostly in b/w, colour figures. 8 slides per A4 page.


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