Tasks for WFI spectroscopic data processing are distributed between the Science Operations Center (SOC) and the Science Support Center (SSC). The SOC is responsible for producing Level-1 (uncalibrated exposures including metadata and engineering telemetry) and Level-2 (exposures with detector-level signatures removed) calibrated direct imaging and spectroscopic exposures, as well as regularized and mosaic image and image data catalogs (Level-3 and Level-4 data, respectively). The SSC is responsible for processing (extracting and fitting) spectroscopic data to produce spectroscopic Level-4 data products, including 1D spectra and catalogs of fitted quantities for each spectrum. This happens in the Science Data Pipeline (SDP). The SDP uses the Level-3 images and Level-4 image catalogs to identify, locate, extract, calibrate, and fit the Roman grism and prism spectra, returning Level-4 science data, and corresponding data quality flags and files, to the Roman archive. The SSC is also responsible for the development and implementation of the Calibration Data Pipeline (CDP), which analyzes calibration data to produce the calibration reference files used by the Science Data Pipeline (SDP). The calibration reference files are also delivered to the Roman archive. The CDP and the SDP are the main elements of the Grism/Prism Data Processing System (GDPS). 

The SDP is based on the Euclid slitless spectroscopy pipeline (Euclid Collaboration, 2025, arXiv:2503.15307; arXiv:2503.15308), and has been developed in consultations with the Euclid NASA Science Center (ENSCI) at IPAC, the Euclid (Spectroscopy-IR) SIR team and the Euclid (Spectroscopy) SPE team, in particular the Laboratoire d’Astrophysique de Marseille (LAM). 

Grism-Prism Data Processing System (GDPS)

Pipeline Processing and Data Flow

After transmission to the ground system, Level-0 Roman spectroscopic data will be transmitted to the Science Operations Center (SOC) at STScI, which will process them to Level-1 (uncalibrated exposures including metadata and engineering telemetry) and Level-2 (exposures with detector-level signatures removed).  The corresponding image data will be further processed by the SOC to Level-3 (image mosaics) and Level-4 (image catalogs) by the SOC. The Level-2 grism and prism data, along with the corresponding Level-3 and Level-4 imaging data, will be retrieved by the SSC for processing to Level-4 in the GDPS. The SSC will transfer all Level-4 spectroscopic data products, relevant calibration reference files, and appropriate documentation to the Roman archive at MAST. The operational interfaces and basic data flow for the GDPS are shown in Figure 1.

References

• Euclid Collaboration et al. 2025, A&A, 697, A1; 2025, arXiv:2503.15307; 2025, arXiv:2503.15308.