Flat field errors and intra-pixel sensitivities for non-redundant aperture masking interferometry on JWST NIRISS

摘要

The James Webb Space Telescope (JWST) is equipped with a 7-hole non-redundant mask on the Near IR Imager and Slitless Spectrograph (NIRISS). Flat field error is likely to limit the contrast of this imaging mode. This can be mitigated by placing calibrator and target on the same pixel. Image plane modeling, using measured intra-pixel sensitivities, enables us to determine the target and calibrator placements to a fraction of a pixel. This is helpful given the barely Nyquist pixel scale on NIRISS and non-uniform sensitivity within the pixel. We discuss the effects of coarse sampling and varied intra-pixel response across the detector on the contrast of JWST AMI. We additionally explore the combination of the sub-Nyquist sampled F277W filter with the mask. Using the F277W filter with NRM will expand the planet formation science possible for JWST.