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Monday, March 08, 2004

Linking Stellar interferometry and Harmonic Analysis

In Boone's thesis on dynamical configuration of interferometers for the study of galaxies, one can read two articles eventually published in "Astronomy and Astrophysics". For the first time, a software is written describing how pairs of telescopes should be located to obtain good images. The interesting point is that in interferometry, the positioning of the telescopes is directly related to a location in the fourier space or the u-v space as they call it. What I find fascinating is that Boone's program does not seem to take into account what he is looking at. If one does not have a preconceived idea of what one is looking for, this is fine. However, the recent use of new harmonic tools like curvelets to decompose astronomical images tells us that a large reduction of observations in the u-v plane could be achieved. The idea is as follows: each curvelet has a very specific and known shape in the u-v plane (or fourier space, see courses by Jean-luc Stark or papers by David Donoho). Astronomical images are decomposed nearly optimally in this curvelet basis, hence a small amount of evaluation in the u-v plane should enable one to recover the whole fourier transform of the astronomical image being sought.

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