BOSKRI , Abdelkarim

In the last few years, specialists in optical interferometry have produced many reference publications with important new astrophysical results, mainly in the field of stellar physics, with recent progress in the study of active galactic nuclei and several results in planetary science. Decisive breakthroughs are expected from the second...

The next generation of fringe tracker (FT) is intended to allow continuous fringe observation and to improve significantly the sensitivity of the interferometer. A promising control approach is presented to cope with contradictory requirements. The FT system must be accurate and stable, which implies high frequency sampling of the optical path...

The Planet Formation Imager (PFI) is a project for a very large optical interferometer intended to obtain images of the planet formation process at scales as small as the Hill sphere of giant exoplanets. Its main science instruments will work in the thermal infrared but it will be cophased in the near infrared, where it requires also some...

International audience

ABSTRACT The spectacular results provided by the second-generationVLTI instruments GRAVITY and MATISSE on active galactic nuclei (AGN) trigger and justify a strong increase in the sensitivity limit of optical interferometers. A key component of such an upgrade is off-axis fringe tracking. To evaluate its potential and limitations, we describe...

Hierarchical Fringe Tracking (HFT) is a fringe tracking concept optimizing the sensitivity in optical long baseline by reducing to an absolute minimum the number of measurements used to correct the OPD fluctuations. By nature, the performances of an HFT do not decreases with the number of apertures of the interferometer and are set only by the...

The VLTI has a huge potential for the study of Active Galactic Nuclei. It allows to resolve the BLR by phase differential interferometry and to make images of the inner dust « torus ». The first generation VLTI instruments AMBER and MIDI allowed studies of the size-luminosity of the inner dust structures and showed strong departures from the...