Bibcode
Filho, Mercedes E.; Garcia, Paulo; Duvert, Gilles; Duchene, Gaspard; Thiebaut, Eric; Young, John; Absil, Olivier; Berger, Jean-Phillipe; Beckert, Thomas; Hoenig, Sebastian; Schertl, Dieter; Weigelt, Gerd; Testi, Leonardo; Tatuli, Eric; Borkowski, Virginie; de Becker, Micha"l.; Surdej, Jean; Aringer, Bernard; Hron, Joseph; Lebzelter, Thomas; Chiavassa, Andrea; Corradi, Romano; Harries, Tim
Bibliographical reference
Optical and Infrared Interferometry. Edited by Schöller, Markus; Danchi, William C.; Delplancke, Françoise. Proceedings of the SPIE, Volume 7013, pp. 70131F-70131F-12 (2008).
Advertised on:
7
2008
Citations
0
Refereed citations
0
Description
One of the aims of next generation optical interferometric
instrumentation is to be able to make use of information contained in
the visibility phase to construct high dynamic range images. Radio and
optical interferometry are at the two extremes of phase corruption by
the atmosphere. While in radio it is possible to obtain calibrated
phases for the science objects, in the optical this is currently not
possible. Instead, optical interferometry has relied on closure phase
techniques to produce images. Such techniques allow only to achieve
modest dynamic ranges. However, with high contrast objects, for faint
targets or when structure detail is needed, phase referencing techniques
as used in radio interferometry, should theoretically achieve higher
dynamic ranges for the same number of telescopes. Our approach is not to
provide evidence either for or against the hypothesis that phase
referenced imaging gives better dynamic range than closure phase
imaging. Instead we wish to explore the potential of this technique for
future optical interferometry and also because image reconstruction in
the optical using phase referencing techniques has only been performed
with limited success. We have generated simulated, noisy, complex
visibility data, analogous to the signal produced in radio
interferometers, using the VLTI as a template. We proceeded with image
reconstruction using the radio image reconstruction algorithms contained
in aips imagr (clean algorithm). Our results show that image
reconstruction is successful in most of our science cases, yielding
images with a 4 milliarcsecond resolution in K band. We have also
investigated the number of target candidates for optical phase
referencing. Using the 2MASS point source catalog, we show that there
are several hundred objects with phase reference sources less than 30
arcseconds away, allowing to apply this technique.