International colloquium at Haute-Provence Observatory, France, 23 - 27 September, 2013



International colloquium at Haute-Provence Observatory, France, 23 - 27 September 2013

Improving the performances of current optical interferometers & future designs


Goal of the colloquium:

The number of astrophysical studies making use of interferometers has steadily increased during the past 15 years. Nevertheless, the performances of interferometers are still limited: their sensitivity does not exceed the magnitude V=10, and their imaging capability could yet be improved by increasing the number of telescopes/sub-apertures. Many interesting astrophysical objects remain out of reach. Moreover, in the context of the ELTs, it is not certain how future interferometry projects will be financed. However, interferometry remains the only way to observe compact astrophysical objects with a very high angular resolution (< milliarcsecond). High angular resolution should still improve, for quite some time, our knowledge on the universe, for example by imaging gravitational micro-lensing events, the central engines of AGN, proto-planetary disks, exo-planets, etc.


This workshop is partly dedicated to the technologies that could improve the performances of interferometers: optimized telescope array geometries, solutions with and without delay-lines, fringe tracking optimizations, and « Adaptive Optics » for diluted telescopes, progress in the field of optical fibers and integrated optics, focal recombiner, etc. Experiment reports, new optical designs to improve the sensitivity and the quality of interferometer observables (accuracy on the visibilities, and closure phases), and any new theoretical ideas are particularly welcome. Presentations on new telemetry techniques for very accurate delay-line positioning, in particular for astrometry, are encouraged. Progress in the field of nulling interferometry are also welcome. We plan to discuss the best optical design for a post-VLTI facility. In this context, several talks on astrophysical goals achievable with such an interferometer will be selected.

Main topics of the workshop include:
  • Optical designs for the future interferometers
  • Techniques to improve the accuracy of the measurements (visibility, closure-phases, etc.)
  • Progress on the delay-line performances
  • Solutions without delay-lines
  • Technologies that could allow larger apertures at lower cost (ex: lightweight replica mirrors)
  • Optimized beam combiners (integrated optics, temporal hypertelescope, pupil densifier, etc.)
  • Fringe tracking systems
  • Laser telemetry applied to interferometry
  • Heterodyne interferometer
  • Progress in image reconstruction techniques (strategy about the ideal uv coverage depending on the observed astrophysical objects, etc.)
  • Progress in the field of nulling interferometry
  • Important science cases that could benefit from progress in interferometry (report of observations at the limit of the performances of the present systems)