Astron. Astrophys. Suppl. Ser.
Volume 116, Number 3, May 1 1996
|Page(s)||597 - 610|
|Published online||15 May 1996|
Diffraction limited near-infrared imaging of the Red Rectangle by bispectral analysis
Observatoire de la Côte d'Azur, Département Fresnel (URA CNRS 1361), Av. Copernic, F-06130 Grasse, France
2 Laboratoire d'Astrophysique (URA CNRS 708), Observatoire de Grenoble, Université Joseph-Fourier, BP. 53X, F-38041 Grenoble Cedex, France
3 Observatoire de la Côte d'Azur, Département Fresnel (URA CNRS 1361), BP. 229, F-06034 Nice Cedex 4, France
4 Max-Planck-Institut für Extraterrestrische Physik, Postfach 1603, D-85740 Garching, Germany
5 Observatoire de Paris-Meudon, Département Spatial, URA CNRS, 92195 Meudon Cedex, France
Corresponding author: Send offprint request to: P. Cruzalèbes; firstname.lastname@example.org
Accepted: September 1995
We present a new method for infrared speckle imaging mainly based on the bispectral analysis algorithm applied to extended objects. The efficiency of the reconstruction procedure is increased by a relaxation process making use of redundancies in the pupil plane. The method is applied to near- and mid-infrared data sets of the Red Rectangle (CRL 915) in K, L' and M-bands leading to diffraction limited maps of the post-AGB (Asymptotic Giant Branch) bipolar nebula. Studying the morphology of the Red Rectangle at sub-second of arc scale allows to decompose the near and mid-infrared broadband spectrum in two parts: the radiated light from the central part of the nebula and the radiated light from the lobes to the north and south. This decomposition indicates that, in addition to scattering of the light from a central source, thermal extended emission from warm dust may also be important at arsecond and subarcsecond scales in this bipolar nebula.
Key words: infrared: ISM: continuum / planetary nebulae: individual (CRL 915) / stars: individual (HD44179) / techniques: image processing / techniques: interferometric
© European Southern Observatory (ESO), 1996