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Proceedings Paper

LITpro: a model fitting software for optical interferometry
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Paper Abstract

LITpro is a software for fitting models on data obtained from various stellar optical interferometers, like the VLTI. As a baseline, for modeling the object, it provides a set of elementary geometrical and center-to-limb darkening functions, all combinable together. But it is also designed to make very easy the implementation of more specific models with their own parameters, to be able to use models closer to astrophysical considerations. So LITpro only requires the modeling functions to compute the Fourier transform of the object at given spatial frequencies, and wavelengths and time if needed. From this, LITpro computes all the necessary quantities as needed (e.g. visibilities, spectral energy distribution, partial derivatives of the model, map of the object model). The fitting engine, especially designed for this kind of optimization, is based on a modified Levenberg-Marquardt algorithm and has been successfully tested on real data in a prototype version. It includes a Trust Region Method, minimizing a heterogeneous non-linear and non-convex criterion and allows the user to set boundaries on free parameters. From a robust local minimization algorithm and a starting points strategy, a global optimization solution is effectively achieved. Tools have been developped to help users to find the global minimum. LITpro is also designed for performing fitting on heterogeneous data. It will be shown, on an example, how it fits simultaneously interferometric data and spectral energy distribution, with some benefits on the reliability of the solution and a better estimation of errors and correlations on the parameters. That is indeed necessary since present interferometric data are generally multi-wavelengths.

Paper Details

Date Published: 28 July 2008
PDF: 9 pages
Proc. SPIE 7013, Optical and Infrared Interferometry, 70131J (28 July 2008); doi: 10.1117/12.788871
Show Author Affiliations
I. Tallon-Bosc, Univ. de Lyon (France)
Univ. de Lyon 1, Observatoire de Lyon (France)
CNRS-Ctr. de Recherche Astrophysique de Lyon (France)
M. Tallon, Univ. de Lyon (France)
Univ. de Lyon 1, Observatoire de Lyon (France)
CNRS-Ctr. de Recherche Astrophysique de Lyon (France)
E. Thiébaut, Univ. de Lyon (France)
Univ. de Lyon 1, Observatoire de Lyon (France)
CNRS-Ctr. de Recherche Astrophysique de Lyon (France)
C. Béchet, Univ. de Lyon (France)
Univ. de Lyon 1, Observatoire de Lyon (France)
CNRS-Ctr. de Recherche Astrophysique de Lyon (France)
G. Mella, Lab. d'Astrophysique de Grenoble, CNRS (France)
S. Lafrasse, Lab. d'Astrophysique de Grenoble, CNRS (France)
O. Chesneau, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur (France)
A. Domiciano de Souza, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur (France)
G. Duvert, Lab. d'Astrophysique de Grenoble, CNRS (France)
D. Mourard, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur (France)
R. Petrov, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur (France)
M. Vannier, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur (France)


Published in SPIE Proceedings Vol. 7013:
Optical and Infrared Interferometry
Markus Schöller; William C. Danchi; Françoise Delplancke, Editor(s)

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