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D. Leisawitz, D. Leviton, A. Martino, W. Maynard (NASA GSFC), L.G. Mundy (U. Maryland and NASA Faculty Fellow), S.A. Rinehart (NRC Research Assoc., NASA GSFC), X. Zhang (RITSS, NASA GSFC), WIIT Science and Technical Advisory Group Team
We describe the technique of wide field mosaic imaging for optical/IR interferometers and present early experimental results from a laboratory instrument designed to validate, experiment with, and refine the technique. A conventional single-detector stellar interferometer operating with narrow bandwidth at center wavelength \lambda is limited in its field of view to the primary beam of the individual telescope apertures, or ~\lambda / Dtel radians, where Dtel is the telescope diameter. Such a field is too small for many applications; often one wishes to image extended sources. We are developing and testing a technique analogous to the mosaicing method employed in millimeter and radio astronomy, but applicable to optical/IR Michelson interferometers, in which beam combination is done in the pupil plane. An Npix x Npix array detector placed in the image plane of the interferometer is used to record simultaneously the fringe patterns from many contiguous telescope fields, effectively multiplying the field size by Npix/2, where the factor 2 allows for Nyquist sampling. This technology will be especially valuable for far IR and submillimeter interferometric space observatories such as the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). SPIRIT and SPECS will be designed to provide sensitive, high angular resolution observations of fields several arcminutes in diameter, and views of the universe complementary to those provided by HST, NGST, and ALMA.
Funding for WIIT is provided by NASA Headquarters through the ROSS/SARA Program and by the Goddard Space Flight Center through its IR&D Program.
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The author(s) of this abstract have provided an email address for comments about the abstract: mailto: leisawitz@stars.gsfc.nasa.gov