First statistics of the isopistonic angle for long baseline interferometry

A. Ziad (1) , T. Elhalkouj (2) , R. Petrov (1) , J. Borgnino (1) , M. Lazrek (2) , Z. Benkhaldoun (2) , F. Martin (1) , Y. Elazhari (2)

1 LAGRANGE - Joseph Louis LAGRANGE
2 LPHEA - Laboratoire de Physique des Hautes Energies et d'Astrophysique

To reach a suitable limiting magnitude with a multi-aperture interferometer, we need to cophase the different telescopes using a reference source. The latter should be located in the same isopistonic domain as the science source. We developed a direct analytical expression of deducing the isopistonic angle from atmospheric optical parameters as seeing, isoplanatic angle and outer scale. All of these atmospheric turbulence parameters are measured by the Generalized Seeing Monitor (GSM). The first statistics of the isopistonic angle obtained from the GSM data are presented and comparison between the major sites over the world are discussed (La Silla, Cerro Pachon, Paranal, San Pedro, Mt Palomar, Mauna Kea, La Palma, Ouka ̈ımeden, Maydanak, Dome C). Implications of these isopistonic angle statistics on large interferometers cophasing in terms of sky coverage and limiting magnitude are discussed.

Mots clés: atmospheric effects; instrumentation: high angular resolution; instrumentation: interferometers; site testing

Domaines: Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]

A. Ziad, T. Elhalkouj, R. Petrov, J. Borgnino, M. Lazrek, et al.. First statistics of the isopistonic angle for long baseline interferometry. Monthly Notices of the Royal Astronomical Society, 2016, 458 (4), pp.4044-4051. ⟨10.1093/mnras/stw366⟩. ⟨hal-03539950⟩