The Transiting Exoplanet Community Early Release Science Data Challenge #1: Lessons for NIRCam Spectroscopic Time-Series Analysis

The Transiting Exoplanet Community Early Release Science (ERS) Program produced a simulated transit of WASP-39b as would be observed by NIRCam. The data consist of both short wavelength (SW) imaging and long wavelength (LW) spectroscopy using the F210 M (2.1 microns) and F322W2 (2.4–4.0 microns) filters, respectively. The GRISMR disperser yields a resolution of R ~ 1700. Two full simulations were produced. The first contains only the astrophysical model of the transit. The second contains the astrophysical model as well as systematic, correlated noise sources. Stage 0 (raw, uncalibrated frame data), 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 iIntercomparisons of reduced data, light curves, models and transmission spectra. We describe the simulated data products and report on the lessons learned from this ERS Data Challenge regarding NIRCam 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.