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Arxiv: The JWST Emission Line Survey (JELS): Extending rest-optical narrow-band emission line selection into the Epoch of Reionization Published: 10/11/2024 8:13:39 PM Updated: 11/6/2024 3:55:12 PM

Paper abstract: We present the JWST Emission Line Survey (JELS), a Cycle 1 JWST imagingprogramme exploiting the wavelength coverage and sensitivity of NIRCam toextend narrow-band rest-optical emission line selection into the epoch ofreionization (EoR) for the first time, and to enable unique studies of theresolved ionised gas morphology in individual galaxies across cosmic history.The primary JELS observations comprise ~4.7\mum narrow-band imaging over~63 arcmin^{2} designed to enable selection of H\alpha emitters atz~6.1, as well as the selection of a host of novel emission-line samplesincluding [OIII] at z~8.3 and Pa \alpha/\beta at z~1.5/2.8. For theprime F466N and F470N narrow-band observations, the emission-line sensitivitiesachieved are up to ~2\times more sensitive than current slitlessspectroscopy surveys (5\sigma limits of 1.1-1.6\times10^{-18}\text{ergs}^{-1}\text{cm}^{-2}), corresponding to unobscured H\alpha star-formationrates (SFRs) of 1-1.6 \text{M}_{\odot}\,\text{yr}^{-1} at z~6.1 andextending emission-line selections in the EoR to fainter populations.Simultaneously, JELS also obtained F200W broadband and F212N narrow-bandimaging (H\alpha at z~2.23) that probes SFRs \gtrsim5\times fainterthan previous ground-based narrow-band studies (~0.2\text{M}_{\odot}\text{yr}^{-1}), offering an unprecedented resolved view ofstar formation at cosmic noon. In this paper we describe the detailed JELSsurvey design, key data processing steps specific to the survey observations,and demonstrate the exceptional data quality and imaging sensitivity achieved.We then summarise the key scientific goals of JELS and present some earlyscience results, including examples of spectroscopically confirmed H\alphaand [OIII] emitters discovered by JELS that illustrate the novel parameterspace probed.