TY - GEN

T1 - Astrometric and Wavelength Calibration of the NIRSpec Instrument during Commissioning using a model-based approach

AU - Lutzgendorf, Nora

AU - Giardino, Giovanna

AU - Alves de Oliveira, Catarina

AU - Zeidler, Peter

AU - Ferruit, Pierre

AU - Jakobsen, Peter

AU - Kumari, Nimisha

AU - Rawle, Tim

AU - Birkmann, Stephan M.

AU - Boker, Torsten

AU - Proffitt, Charles

AU - Sirianni, Marco

AU - Te Plate, Maurice

AU - Sohn, Sangmo Tony

PY - 2022/8/27

Y1 - 2022/8/27

N2 - The NIRSpec instrument for the James Webb Space Telescope (JWST) is a highly versatile near-infrared spectrograph that can be operated in various observing modes, slit apertures, and spectral resolutions. Obtaining dedicated calibration data for all possible combinations of aperture and disperser is an intractable task. We have therefore developed a procedure to derive a highly realistic model of the instrument's optical geometry across the entire field of view, using calibration data acquired through only a subset of NIRSpec apertures, which nevertheless allows the light paths within the spectrograph to be accurately computed for all apertures and all observing modes. This parametric instrument model thus provides the basis for the extraction of wavelength-calibrated spectra from any NIRSpec exposure, regardless of observing mode or aperture used. Optimizing the NIRSpec instrument model and deriving its final wavelength and astrometric calibration was one of the most crucial elements of the NIRSpec commissioning phase. Here, we describe the process of re-fitting the NIRSpec instrument model with in-orbit commissioning data, and present its final performance in terms of wavelength accuracy and astrometric calibration.

AB - The NIRSpec instrument for the James Webb Space Telescope (JWST) is a highly versatile near-infrared spectrograph that can be operated in various observing modes, slit apertures, and spectral resolutions. Obtaining dedicated calibration data for all possible combinations of aperture and disperser is an intractable task. We have therefore developed a procedure to derive a highly realistic model of the instrument's optical geometry across the entire field of view, using calibration data acquired through only a subset of NIRSpec apertures, which nevertheless allows the light paths within the spectrograph to be accurately computed for all apertures and all observing modes. This parametric instrument model thus provides the basis for the extraction of wavelength-calibrated spectra from any NIRSpec exposure, regardless of observing mode or aperture used. Optimizing the NIRSpec instrument model and deriving its final wavelength and astrometric calibration was one of the most crucial elements of the NIRSpec commissioning phase. Here, we describe the process of re-fitting the NIRSpec instrument model with in-orbit commissioning data, and present its final performance in terms of wavelength accuracy and astrometric calibration.

KW - James Webb Space Telescope

KW - JWST

KW - Near-Infrared Spectrograph

KW - NIRSpec

KW - Commissioning

KW - Wavelength Calibration

KW - Astrometric Calibration

KW - INFRARED SPECTROGRAPH NIRSPEC

U2 - 10.1117/12.2630069

DO - 10.1117/12.2630069

M3 - Conference article

VL - 12180

JO - Progress in Biomedical Optics and Imaging

JF - Progress in Biomedical Optics and Imaging

SN - 1605-7422

M1 - 121800Y

T2 - Conference on Space Telescopes and Instrumentation - Optical, Infrared, and Millimeter Wave

Y2 - 17 July 2022 through 22 July 2022

ER -