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Issue A&A
Volume 418, Number 2, May I 2004
Page(s) 771 - 780
Section Instruments, observational techniques, and data processing
DOI http://dx.doi.org/10.1051/0004-6361:20040055



A&A 418, 771-780 (2004)
DOI: 10.1051/0004-6361:20040055

Analysis of spectro-imaging data using the Karhunen-Loève expansion: Application to NGC 7027 in the infrared

D. Mékarnia1, A. Bijaoui1, C. Delle Luche2 and J. P. Maillard3

1  Dpt Cassiopée, CNRS UMR-6202, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France
2  ESO, Alonso de Cordova 3107, Vitacura Santiago 19, Chile
3  Institut d'Astrophysique de Paris, 98 bis Bd Arago, 75014 Paris, France

(Received 22 January 2003 / Accepted 15 January 2004)

Abstract
A method, based on the Karhunen-Loève (KL) transformation, to improve the signal-to-noise ratio of a multispectral data cube is presented. As an illustration we have re-analyzed near-infrared multi-spectral images of the young planetary nebula NGC 7027 previously observed by Cox et al. (2002). Our KL analysis clearly shows an enhancement of both spectral and spatial information, particularly in the case of low signal-to-noise ratio images.


Key words: methods: data analysis -- planetary nebulae: individual: NGC 7027

Offprint request: D. Mékarnia, mekarnia@obs-nice.fr

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© ESO 2004


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