The JWST Emission-Line Survey: Extending rest-optical narrow-band emission-line selection into the Epoch of Reionization
Duncan KJ, Mcleod DJ, Best PN, Pirie CA, Clausen M, Cochrane RK, Dunlop JS, Flury SR, Geach JE, Grogin NA, Hale CL, Ibar E, Kondapally R, Li Z, Matthee JJ, Mclure RJ, Ossa-Fuentes L, Patrick AL, Smail I, Sobral D, Stephenson HMO, Stott JP, Swinbank AM. 2025. The JWST Emission-Line Survey: Extending rest-optical narrow-band emission-line selection into the Epoch of Reionization. Monthly Notices of the Royal Astronomical Society. 541(2), 1329–1347.
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Author
Duncan, K. J.;
Mcleod, D. J.;
Best, P. N.;
Pirie, C. A.;
Clausen, M.;
Cochrane, R. K.;
Dunlop, J. S.;
Flury, S. R.;
Geach, J. E.;
Grogin, N. A.;
Hale, C. L.;
Ibar, E.
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All
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Abstract
We present the JWST Emission-Line Survey (JELS), a JWST imaging programme exploiting the wavelength coverage and sensitivity of the Near-Infrared Camera (NIRCam) to extend narrow-band rest-optical emission-line selection into the Epoch of Reionization (EoR) for the first time, and to enable unique studies of the resolved ionized gas morphology in individual galaxies across cosmic history. The primary JELS observations comprise ∼ 4.7 μm narrow-band imaging over ∼ 63 arcmin2 designed to enable selection of H α emitters at z ∼ 6.1 and a host of novel emission-line samples, including [O III] (z ∼ 8.3) and Paschen α/β (z ∼ 1.5/2.8). For the F466N/F470N narrow-band observations, the emission-line sensitivities achieved are up to ∼ 2× more sensitive than current slitless spectroscopy surveys (5σ limits of 0.8–1.2×10−18 erg s−1cm−2), corresponding to unobscured H α star formation rates (SFRs) of 0.9–1.3 M yr−1 at z ∼ 6.1, extending emission-line selections in the EoR to fainter populations. Simultaneously, JELS also adds F200W broad-band and F212N narrow-band imaging (H α at z ∼ 2.23) that probes SFRs 5× fainter than previous ground-based narrow-band studies (∼ 0.2 M yr−1), offering an unprecedented resolved view of star formation at cosmic noon. We present the detailed JELS design, key data processing steps specific to the survey observations, and demonstrate the exceptional data quality and imaging sensitivity achieved. We then summarize the key scientific goals of JELS, demonstrate the precision and accuracy of the expected redshift and measured emission-line recovery through detailed simulations, and present examples of spectroscopically confirmed H α and [O III] emitters discovered by JELS that illustrate the novel parameter space probed.
Publishing Year
Date Published
2025-08-01
Journal Title
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press
Acknowledgement
We thank the anonymous referee for their helpful and constructive feedback that hassignificantly improved this manuscript. The authors also thank DavidCoulter and ArminRestfor allowing the inclusion of JELS targets in their director’s discretionary observing programme. KJD acknowledges support from the Science and Technology Facilities Council (STFC) through an Ernest Rutherford Fellowship (grant number ST/W003120/1). DJM, PNB, RK, and RJM acknowledge the support of the UK STFC via grant ST/V000594/1. PNB and RK are grateful for support from the UK STFC via grant ST/Y000951/1. RKC was funded by support for programme #02321, provided by NASA through a grant from the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-03127. RKC is grateful for support from the Leverhulme Trust via the Leverhulme Early Career Fellowship.JSD acknowledgesthe support of the Royal Society via a Royal Society Research Professorship. CLH acknowledges support from the Leverhulme Trust through an Early Career Research Fellowship and also acknowledge support from the Oxford
Hintze Centre for Astrophysical Surveys which is funded through generous support from the Hintze Family Charitable Foundation. EI gratefully acknowledge financial support from ANID –MILENIO – NCN2024 112 and ANID FONDECYT Regular 1221846. AMS and IRS acknowledge support from the STFC via grant ST/X001075/1.This work was initiated in part at Aspen Center for Physics, which is supported by National Science Foundation grant PHY-2210452.
Volume
541
Issue
2
Page
1329-1347
ISSN
eISSN
IST-REx-ID
Cite this
Duncan KJ, Mcleod DJ, Best PN, et al. The JWST Emission-Line Survey: Extending rest-optical narrow-band emission-line selection into the Epoch of Reionization. Monthly Notices of the Royal Astronomical Society. 2025;541(2):1329-1347. doi:10.1093/mnras/staf1061
Duncan, K. J., Mcleod, D. J., Best, P. N., Pirie, C. A., Clausen, M., Cochrane, R. K., … Swinbank, A. M. (2025). The JWST Emission-Line Survey: Extending rest-optical narrow-band emission-line selection into the Epoch of Reionization. Monthly Notices of the Royal Astronomical Society. Oxford University Press. https://doi.org/10.1093/mnras/staf1061
Duncan, K. J., D. J. Mcleod, P. N. Best, C. A. Pirie, M. Clausen, R. K. Cochrane, J. S. Dunlop, et al. “The JWST Emission-Line Survey: Extending Rest-Optical Narrow-Band Emission-Line Selection into the Epoch of Reionization.” Monthly Notices of the Royal Astronomical Society. Oxford University Press, 2025. https://doi.org/10.1093/mnras/staf1061.
K. J. Duncan et al., “The JWST Emission-Line Survey: Extending rest-optical narrow-band emission-line selection into the Epoch of Reionization,” Monthly Notices of the Royal Astronomical Society, vol. 541, no. 2. Oxford University Press, pp. 1329–1347, 2025.
Duncan KJ, Mcleod DJ, Best PN, Pirie CA, Clausen M, Cochrane RK, Dunlop JS, Flury SR, Geach JE, Grogin NA, Hale CL, Ibar E, Kondapally R, Li Z, Matthee JJ, Mclure RJ, Ossa-Fuentes L, Patrick AL, Smail I, Sobral D, Stephenson HMO, Stott JP, Swinbank AM. 2025. The JWST Emission-Line Survey: Extending rest-optical narrow-band emission-line selection into the Epoch of Reionization. Monthly Notices of the Royal Astronomical Society. 541(2), 1329–1347.
Duncan, K. J., et al. “The JWST Emission-Line Survey: Extending Rest-Optical Narrow-Band Emission-Line Selection into the Epoch of Reionization.” Monthly Notices of the Royal Astronomical Society, vol. 541, no. 2, Oxford University Press, 2025, pp. 1329–47, doi:10.1093/mnras/staf1061.
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