Co-phasing of a diluted aperture synthesis instrument for direct imaging II. Experimental demonstration in the photon-counting regime with a temporal hypertelescope

• Published in: Astronomy and astrophysics (Berlin) Vol. 567; p. np
• Main Authors: Bouyeron, L, Delage, L, Baudoin, R, Gomes, J T, Grossard, L, Reynaud, F
• Format: Journal Article
• Language: English
• Published: 01.07.2014
• Subjects: Apertures; Architecture; Arrays; Constraining; Genetic algorithms; Imaging; Photons; Telescopes
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201321486

Amongst the new techniques currently developed for high-resolution and high-dynamics imaging, the hypertelescope architecture is very promising for direct imaging of objects such as exoplanets. The performance of this instrument strongly depends on the co-phasing process accuracy. In a previous high-flux experimental study with an eight-telescope array, we successfully implemented a co-phasing system based on the joint use of a genetic algorithm and a sub-aperture piston phase diversity using the object itself as a source for metrology. To fit the astronomical context, we investigate the impact of photon noise on the co-phasing performance operating our laboratory prototype at low flux. This study provides experimental results on the sensitivity and the dynamics that could be reached for real astrophysical observations. This laboratory experiment demonstrates the potential of our hypertelescope concept, which could be directly transposed to a space-based telescope array. Assuming eight telescopes with a 30 cm diameter, the I-band limiting magnitude of the main star would be 7.3, allowing imaging of a companion with a 17.3 mag.