Optimal Method for Exoplanet Detection by Spectral and Angular Differential Imaging

Abstract

In the context of the SPHERE planet finder project, we further develop a recently proposed method, based on detection theory, for the efficient detection of planets using spectral and angular differential imaging. The proposed method uses the fact that with the SPHERE instrument the eld rotates during the night, and that at each acquisition time, two images are recorded by the IRDIS instrument in two different spectral channels. The method starts with the appropriate combination of images recorded at different times, and potentially in different spectral channels, into so-called pseudo-data. It then uses jointly all these pseudo-data in a Maximum-Likelihood (ML) framework to detect the position and amplitude of potential companions of the observed star, taking into account the mixture of photon and detector noises. The method is validated on simulated data.