The Near-Infrared Spectrograph (NIRSpec) is one of the four focal plane instruments on the James Webb Space Telescope which was launched on Dec. 25, 2021. We present an overview of the as-run NIRSpec commissioning campaign, with particular emphasis on the sequence of activities that led to the verification of all hardware components of NIRSpec. We also discuss the mechanical, thermal, and operational performance of NIRSpec, as well as the readiness of all NIRSpec observing modes for use in the upcoming JWST science program.
The Near InfraRed Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST) includes a novel micro shutter array (MSA) to perform multi object spectroscopy. While the MSA is mainly targeting galaxies across a larger field, it can also be used for studying star formation in crowded fields. Crowded star formation regions typically feature strong nebular emission, both in emission lines and continuum. In this work, nebular emission is referred to as nebular contamination. Nebular contamination can obscure the light from the stars, making it more challenging to obtain high quality spectra. The amount of the nebular contamination mainly depends on the brightness distribution of the observed ‘scene’. Here we focus on 30 Doradus in the Large Magellanic Cloud, which is part of the NIRSpec GTO program. Using spectrophotometry of 30 Doradus from the Hubble Space Telescope (HST) and the Very Large Telescope (VLT)/SINFONI, we have created a 3D model of the nebular emission of 30 Doradus. Feeding the NIRSpec Instrument Performance Simulator (IPS) with this model allows us to quantify the impact of nebular emission on target stellar spectra as a function of various parameters, such as configuration of the MSA, angle on the sky, filter band, etc. The results from these simulations show that the subtraction of nebular contamination from the emission lines of pre-main sequence stars produces a typical error of 0.8%, with a 1σ spread of 13%. The results from our simulations will eventually be compared to data obtained in space, and will be important to optimize future NIRSpec observations of massive star forming regions. The results will also be useful to apply the best calibration strategy and to quantify calibration uncertainties due to nebular contamination.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.