Institution(s): 1. National Research Council of Canada
Exoplanet imaging requires high level of stellar flux subtraction. The “angular differential imaging” ADI observing technique and the least-squares LOCI algorithm have now become the standard in the field for single band imaging. With the development of new high-order high-contrast adaptive optics integral field spectrographs, the image subtraction least-squares algorithm needs to be modified to allow the optimal use of polychromatic images, same band/field rotated images and archive data. A new algorithm, TLOCI (for Template LOCI), achieves this task by “maximizing a companion signal-to-noise ratio” instead of the original LOCI “minimizing of the noise”. The TLOCI technique uses an input spectrum and template PSFs to optimize the reference image least-squares coefficients to minimize the flux contamination via self-subtraction (thus maximizing its throughput wavelength per wavelength) of any specific planet in the image, while trying, at the same time, to maximize the noise subtraction. The new algorithm has been developed using on-sky GPI data and has achieved impressive contrast. I will present the TLOCI algorithm and on-sky performances.