The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope III. Integral-field spectroscopy

TL;DR

NIRSpec on JWST provides the first space-based integral-field spectroscopy in the near-infrared, enabling detailed spatial and spectral analysis of celestial objects with high resolution.

Contribution

This paper details the design, expected performance, and observing strategies for NIRSpec's integral-field spectroscopy mode on JWST, a novel capability for space-based near-infrared observations.

Findings

Design of optical and mechanical components described

Expected spectral resolutions of R≈100, 1000, 2700 achieved

Data processing steps for calibrated data cubes outlined

Abstract

The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST) offers the first opportunity to use integral-field spectroscopy from space at near-infrared wavelengths. More specifically, NIRSpec's integral-field unit can obtain spectra covering the wavelength range $0.6 - 5.3~\mu$m for a contiguous 3.1 arcsec $\times$ 3.2 arcsec sky area at spectral resolutions of $R \approx 100$, 1000, and 2700. In this paper we describe the optical and mechanical design of the NIRSpec integral-field spectroscopy mode, together with its expected performance. We also discuss a few recommended observing strategies, some of which are driven by the fact that NIRSpec is a multipurpose instrument with a number of different observing modes, which are discussed in companion papers. We briefly discuss the data processing steps required to produce wavelength- and flux-calibrated data cubes that contain the spatial and spectral information. Lastly, we mention a few scientific topics that are bound to benefit from this highly innovative capability offered by JWST/NIRSpec.