Removing correlated noise stripes from the Nancy Grace Roman Space Telescope survey images

Abstract Weak gravitational lensing has emerged as a powerful tool for investigating the matter distribution in the Universe and how it has evolved over cosmic time. The Wide Field Instrument (WFI) on the Nancy Grace Roman Space Telescope (Roman) will deliver some of the highest precision measurements of weak lensing ever made. Since weak lensing is based on statistics of faint sources, it can be biased by even tiny instrument systematics, including correlated read noise. Previous works have shown the infrared detectors used in the Roman WFI contain correlations in their total noise images at a level significant for weak lensing measurements, even after application of standard reference pixel corrections; of particular concern is $1/f$ noise, which appears as horizontal banding in the detector frame. In this paper, we present imDestripe: a new Python module utilizing the multiple roll angles in Roman’s observing strategy and linear algebra techniques to remove correlated noise stripes from observed images. We test imDestripe in a hybrid simulation by combining real noise realizations (from darks taken during ground testing) with simulated images of the astronomical scene and find that the power spectrum of the banding can be suppressed by factors of 10–30 on large scales. We briefly discuss plans for further development of imDestripe in the context of the WFI pipeline.