The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope

III. Integral-field spectroscopy

¹ European Space Agency, Space Telescope Science Institute, Baltimore, Maryland, USA
e-mail: torsten.boeker@esa.int
² Centro de Astrobiología, (CAB, CSIC–INTA), Departamento de Astrofísica, Madrid, Spain
³ European Space Agency, European Space Astronomy Centre, Madrid, Spain
⁴ Space Telescope Science Institute, Baltimore, Maryland, USA
⁵ Department of Physics, University of Oxford, Oxford, UK
⁶ Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique, Paris, France
⁷ European Space Agency, European Space Research and Technology Centre, Noordwijk, The Netherlands
⁸ ATG Europe for the European Space Agency, European Space Research and Technology Centre, Noordwijk, The Netherlands
⁹ Cosmic Dawn Center, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
¹⁰ AURA for the European Space Agency, Space Telescope Science Institute, Baltimore, Maryland, USA
¹¹ Aurora Technology for the European Space Agency, European Space Astronomy Centre, Madrid, Spain
¹² Kavli Institute for Cosmology, University of Cambridge, Cambridge, UK
¹³ Quantum Circuits, Inc., New Haven, Connecticut, USA
¹⁴ NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
¹⁵ Max-Planck Institute for Astronomy, Heidelberg, Germany
¹⁶ NRC Herzberg, Victoria, British Columbia, Canada

Received: 5 November 2021
Accepted: 28 December 2021

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 μm for a contiguous 3.1″ × 3.2″ sky area at spectral resolutions of R ≈ 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.