Presentation #102.218 in the session Poster Session.
The Transiting Exoplanet Community Early Release Science (ERS) Program produced a simulated transit of WASP-39b as would be observed by NIRSpec in the Bright Object Time-Series (BOTS) mode using the prism disperser spanning 0.6–5.0 microns (SUB512) at R ~ 100. The underlying data for these simulations are those obtained during cryogenic vacuum ground testing (ISIM-CV3) of the NIRSpec instrument and therefore include realistic detector efforts. The primary adjustments to this ISIM-CV3 data are the injection of a transit event, the removal of the first 3808 integrations due to large lamp source variations, and the removal of a wavelength-independent systematic induced by the ISIM-CV3 lamp source. Additionally, the duration of the observation has been artificially extended to cover the full transit of the planet. Stage 1 (calibrated, ramp-fit data) and Stage 2 (flux-calibrated, extracted spectra) outputs and their corresponding reference files were delivered to the community and used as inputs at an open Data Challenge where independent analysis tools could be compared at multiple stages of the process. Participants performed intercomparisons of reduced data, light curves, and transmission spectra. We describe the simulated data products and report on the lessons learned from this ERS Data Challenge regarding NIRSpec transmission spectroscopy. We describe the open-source tools currently available and outstanding challenges that drive continued development leading up to the actual JWST observations expected later in the year.