Mitigating Resampling Artifacts for the JWST IFU Spectrometers with Adaptive Trace Modeling

TL;DR

This paper introduces an adaptive spline-based resampling method to significantly reduce artifacts in JWST IFU spectrometer data, improving spectral accuracy across diverse astronomical observations.

Contribution

The authors develop a generalized cubic spline interpolation technique to mitigate resampling artifacts in JWST IFU data, enhancing spectral fidelity and reducing biases.

Findings

Effectively reduces spectral artifacts in JWST data.

Improves spectral accuracy for various astronomical sources.

Applicable to multiple JWST instruments and observation types.

Abstract

The integral-field unit (IFU) spectrometers on board the James Webb Space Telescope (JWST) undersample the nearly diffraction-limited point spread function provided by the telescope optics. This undersampling produces large oscillating spectral artifacts when the data is resampled into regularly-gridded data cubes, which poses a significant challenge for many scientific analyses. We describe here a generalized technique to use cubic basis spline models to interpolate the observed spectral traces onto a higher-resolution grid prior to data cube rectification, which largely eliminates these artifacts in addition to helping reduce biases in point source spectra from clusters of bad pixels. We demonstrate the utility of this adaptive resampling technique for a variety of JWST NIRSpec and MIRI MRS observations ranging from isolated point sources to embedded AGN, crowded stellar fields with diffuse emission, and protostars with rich molecular bands.