Precision Speckle Pattern Reconstruction for High-contrast Imaging

Abstract

In high-contrast imaging, a large instrumental, technological, and algorithmic effort is made to reduce residual speckle noise and improve the detection capabilities. In this work, we explore the potential of using a precise physical description of speckle images, in conjunction with the optimal detection statistic to perform high-contrast imaging. Our method uses short-exposure speckle images, reconstructing the point-spread function (PSF) of each image with phase retrieval algorithms. Using the reconstructed PSFs, we calculate the optimal detection statistic for all images. We analyze the arising bias due to the use of a reconstructed PSF and correct for it completely up to its accumulation over 10 ^4 images. We measure in simulations the method’s sensitivity loss due to overfitting in the reconstruction process and get to an estimated 5 σ detection limit of 5 × 10 ^−7 flux ratio at angular separations of 0.″1–0.″5 for a 1 h observation of Sirius A with a 2 m telescope.

Keywords

• High contrast techniques
• Astronomical seeing
• Astronomy data analysis