Phase Referencing in Optical Interferometry

• Type: Article in International Conference Proceedings Book
• Date: 2008

Authors

Paulo Garcia (Author) FEUP; Mercedes E Filho (Author) FEUP

Conference proceedings International

Title: OPTICAL AND INFRARED INTERFEROMETRY

Conference on Optical and Infrared Interferometry

Marseille, FRANCE, JUN 23-27, 2008

Indexing

ISI Proceedings

ISI Web of Knowledge - 1 Citation

Scopus - 4 Citations

Scientific classification

FOS: Natural sciences > Physical sciences

Other information

Authenticus ID: P-004-4BA

DOI: 10.1117/12.787908

Abstract (EN): One of the aims of next, generation optical interferometric instrumentation is to he 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 phased 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12