Behind the coronagraphic mask


Frantz Martinache


Subaru Telescope


The detection of high contrast companions at small angular separation appears feasible in conventional direct images using the self-calibration properties of interferometric observable quantities. In the high-Strehl regime, soon to be available thanks to the coming generation of extreme Adaptive Optics systems on ground based telescopes, and already available from space, quantities comparable to the closure-phase that are used with great success in non-redundant masking inteferometry, can be extracted from direct images, even taken with a redundant aperture. These new phase-noise immune observable quantities, called kernel-phases, are determined a-priori from the knowledge of the geometry of the pupil only. Re-analysis of archive data acquired with the Hubble Space Telescope NICMOS instrument, using this new kernel-phase algorithm, demonstrates the power of the method, and its ability to detect companions at the resolution limit and beyond, giving a better idea of what is happening "behind the coronagraphic mask".

Attached documents

Lyot2010proc s8 talk MartinacheF.pdf
PDF, 2.5 Mb