An Archival Calibration of JWST/MIRI Prism Wide-Field Slitless Spectroscopy: Methodology, Performance, and a Mid-Infrared Spectral Atlas of Galaxies at z=0−4 in the GOODS-N/S Fields

@misc{sun2026archival,
  title = {{An Archival Calibration of JWST/MIRI Prism Wide-Field Slitless Spectroscopy: Methodology, Performance, and a Mid-Infrared Spectral Atlas of Galaxies at $z=0-4$ in the GOODS-N/S Fields}},
  author = {Fengwu Sun and Javier Álvarez-Márquez and Eiichi Egami and Román Fernández Aranda and Jakob M. Helton and Xiaojing Lin and Jianwei Lyu},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.20935},
  eprint = {2609.20935},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.20935},
  note = {CC0},
}

TY  - UNPB
TI  - An Archival Calibration of JWST/MIRI Prism Wide-Field Slitless Spectroscopy: Methodology, Performance, and a Mid-Infrared Spectral Atlas of Galaxies at z=0−4 in the GOODS-N/S Fields
AU  - Fengwu Sun
AU  - Javier Álvarez-Márquez
AU  - Eiichi Egami
AU  - Román Fernández Aranda
AU  - Jakob M. Helton
AU  - Xiaojing Lin
AU  - Jianwei Lyu
PY  - 2026
DA  - 2026/09/17
PB  - arXiv
DO  - 10.48550/arxiv.2609.20935
UR  - https://arxiv.org/abs/2609.20935
AB  - Through the Low Resolution Spectroscopy (LRS) observing mode of JWST/MIRI, the P750L prism disperses the entire ~70"×110" imager field, turning MIRI into a wide-field slitless spectrograph (WFSS) at 5-14 μm with spectral resolution R∼100. Using archival MIRI LRS data taken in the GOODS-N/S deep fields and calibration programs, we present a complete and precise calibration suite for MIRI WFSS through an AI-assisted agentic workflow under human supervision. The calibration includes flat field, sky background, spectral tracing, wavelength calibration, flux calibration, and the large-scale flux flat (L-flat). We present the methodology of each calibration and quantify its accuracy. As a demonstration, we extract 5-14 μm slitless spectra of 180 spectroscopically confirmed galaxies at z=0.08 − 3.71 in the GOODS-N/S fields. We detect a large number of polycyclic aromatic hydrocarbon (PAH) bands and atomic lines (including Paschen α out to z=3.71) in individual sources. The PAH 3.3 μm luminosities correlate with the Paschen α luminosities (measured through NIRCam WFSS) for z∼1 galaxies over a ∼1.5-dex range, supporting PAH 3.3 μm as a star-formation-rate tracer out to z∼1.6. We release the calibration reference files, reduction scripts, and the mid-infrared spectral atlas. We also present caveats and lessons learned from our archival calibration work. Our empirical sensitivity characterization identifies a noise floor for deep MIRI WFSS integrations (≳ a few ks), whereas shallower integrations exceed the sensitivity predicted by the JWST Exposure Time Calculator. We also provide suggestions for the planning of future MIRI WFSS observing programs.
ER  -