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As another footnote, from probably the most up-to-date, comprehensive, paper I could find on lensing, (the Lensing Bible, I think), an update on the data processing techniques for investigating 'weak lensing', (the up & coming DM characterisation method), going forward into the future:
Source: "The Dark Matter of Gravitational Lensing" by Richard Massey, Thomas Kitching (Institute for Astronomy, Royal Observatory, Blackford Hill, Edinburgh). (Submitted on 12 Jan 2010 (v1), last revised 11 May 2010 (this version, v2))
Summary follows:
" .. it is a challenging inverse problem to start from the observed data and extract the underlying weak lensing signal. Many image analysis techniques have been developed to measure galaxy shapes and correct them for these effects. To make the challenge more difficult still, the most distant galaxies, which contain the largest integrated lensing signal, are very faint and noisy."
The methods used to extract the signal are: KSB Quadrupole Shape Moments, Lenshift and Shapelets, the Shear Testing Program (STEP), GRaviational lEnsing Accuracy Testing scheme (GREAT), the HOLICS estimator and the FLexion Improvement Programme (FLIP).
All have their strengths and weaknesses, ins & outs. (Over to the mathematicians to extract the useful data from the image).
Cheers
PS: I added this snippet for anyone wanting to investigate further. Cheers.
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