Correlated PSF Subtraction Using an Archive

Abstract:

Current high contrast imaging point spread function (PSF) subtraction algorithms all use some form of a least squares noise minimization to construct an optimal reference image using only observations obtained from the same observing sequence (e.g., in angular or spectral differential imaging). The use of reference images over a longer baseline and/or different spectral windows is currently limited by the unknown nature of PSF stability across time and wavelength. We present the results of ongoing work to create a reference PSF library using campaign data from the Gemini Planet Imager Exoplanet Survey (GPIES). This library is designed to construct more correlated reference images over a longer baseline and bandwidth and also to better characterize stability of the GPI PSF. Our work has direct application to improve PSF subtraction algorithms for the GPIES campaign but is more generally applicable to any current or future high contrast imaging survey instrument, such as WFIRST or a second generation ELT planet finder, where this technique will advance our capabilities of directly imaging habitable planets.