Affiliation: Institute for Astronomy, University of Edinburgh

Contribution: Oral

Title: JWST Emission Line Survey: Probing emission-line galaxies into the Epoch of Reionisation

Abstract: The JWST Emission Line Survey (JELS) aims to identify and study ~1000 emission-line selected galaxies across cosmic time using the power of NIRCam narrow-band imaging. Our primary science driver is the detection of ~60 Hα emitters at redshift z>6, out to the Epoch of Reionisation. The Hα emission line is the best-calibrated star-formation indicator in the nearby Universe, and narrow-band imaging surveys have mapped the evolution of Hα emitters out to the peak star-formation epoch at z~2. At higher redshift, samples of star-forming galaxies and estimates of the cosmic star-formation rate density are almost ubiquitously based on rest-frame UV observations; this single approach carries a high risk of systematic effects, both in the populations of galaxies selected and in their derived properties. In this talk, I shall share results from JELS including the search for z>6 Hα emitters, their physical properties along with the first derived Hα luminosity function at this epoch. This is the first critical test in comparing the properties of both Hα and rest-UV selected samples of star-forming galaxies and their contribution to the star-formation rate density at the Epoch of Reionisation. In addition, I will discuss other science goals of the survey including: i) obtaining a fainter sample Hα emitters at z~2, and hence constraining the faint end of the Hα luminosity function at cosmic noon. ii) Utilising NIRCams remarkable angular resolution to measure the ionised gas structures of these star-forming galaxies to sub-kpc resolution. iii) To determine how the relationship between UV and ionised gas structures varies with host galaxy properties, in order to delineate the physical processes driving star formation at these redshifts. And finally, iv) obtain a new sample of other line emission galaxies (e.g. Paschen-α, -β, [OII] and [OIII] emitters) over cosmic time offering a plethora of important scientific opportunities.

This contribution can be found here (pdf).