Stellar intensity interferometry: optimizing air Cherenkov telescope array layouts
Abstract
Kilometric-scale optical imagers seem feasible to realize by intensity interferometry, using telescopes primarily erected for measuring Cherenkov light induced by gamma rays. Planned arrays envision 50-100 telescopes, distributed over some 1-4 km2. Although array layouts and telescope sizes will primarily be chosen for gamma-ray observations, also their interferometric performance may be optimized. Observations of stellar objects were numerically simulated for different array geometries, yielding signal-to-noise ratios for different Fourier components of the source images in the interferometric (u, v)-plane. Simulations were made for layouts actually proposed for future Cherenkov telescope arrays, and for subsets with only a fraction of the telescopes. All large arrays provide dense sampling of the (u, v)-plane due to the sheer number of telescopes, irrespective of their geographic orientation or stellar coordinates. However, for improved coverage of the (u, v)-plane and a wider variety of baselines (enabling better image reconstruction), an exact east-west grid should be avoided for the numerous smaller telescopes, and repetitive geometric patterns avoided for the few large ones. Sparse arrays become severely limited by a lack of short baselines, and to cover astrophysically relevant dimensions between 0.1-3 milliarcseconds in visible wavelengths, baselines between pairs of telescopes should cover the whole interval 30-2000 m.
- Publication:
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Optical and Infrared Interferometry II
- Pub Date:
- July 2010
- DOI:
- 10.1117/12.856412
- arXiv:
- arXiv:1009.5828
- Bibcode:
- 2010SPIE.7734E..1TJ
- Keywords:
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- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 12 pages, 10 figures