Phaseless Mapping From A High-orbit Satellite, Space-Ground Radio Interferometer Options

[ljk4-1]

Paper: astro-ph/0512570

Date: Thu, 22 Dec 2005 15:50:05 GMT (363kb)

Title: A Solution to the Problem of Phaseless Mapping for a High-Orbit
Space-Ground Radio Interferometer

Authors: Anisa T. Bajkova

Comments: 15 pages, 7 figures

Journal-ref: Astronomy Reports, Vol.49, N 12, 2005, pp.973-983
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We consider the problem of mapping with ultra-high angular resolution using a
space-ground radio interferometer with a space antenna in a high orbit,whose
apogee height exceeds the radius of the Earth by a factor of ten. In this case,
a multielement interferometer essentially degenerates into a two-element
interferometer. The degeneracy of the close-phase relations prevents the use of
standard methods for hybrid mapping and self-calibration for the correct
reconstruction of images. We propose a new phaseless mapping method based on
methods for the reconstruction of images in the complete absence of phase
information, using only the amplitudes of the spatial-coherence function of the
source. In connection with this problem, we propose a new method for the
reliable solution of the phase problem, based on optimizing
information-carrying nonlinear functionals, in particular, the Shannon entropy.

Results of simulations of mapping radio sources with various structures with
ultra-high angular resolution in the framework of the RADIOASTRON mission are
presented.

\\ ( http://arXiv.org/abs/astro-ph/0512570 , 363kb)