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Arxiv: UNCOVERing the Faint-End of the z=7 [OIII] Luminosity Function with JWST's F410M Medium Bandpass Filter Published: 7/26/2024 9:03:32 PM Updated: 7/26/2024 9:03:32 PM

Paper abstract: Strong emission from doubly ionized oxygen is a beacon for some of the mostintensely star forming galaxies known. JWST enables the search for this beaconin the early universe with unprecedented sensitivity. In this work, we extendthe study of faint [OIII]_{5008} selected galaxies by an order of magnitudein line luminosity. We use publicly available UNCOVER DR1 JWST/NIRCam and HSTimaging data of the cluster lensing field, Abell 2744, to identify strong(rest-frame EW>500\AA) [OIII]_{5008} emitters at z~7 based on excessF410M flux. We find N=68 z~7 [OIII] candidates, with a subset of N=33that have deep HST coverage required to rule-out lower redshift interlopers(13.68 arcmin^2 with F814W 5\sigma depth >28 AB). Such strong emissionlines can lead to very red colors that could be misinterpreted as evidence forold, massive stellar populations, but are shown to be due to emission lineswhere we have spectra. Using this deep HST sample and completeness simulations,which calculate the effective survey volume of the UNCOVER lensing field as afunction of [OIII] luminosity, we derive a new [OIII] luminosity function (LF)extending to 41.09<\rm{log}_{10}(L/\rm{erg\,s}^{-1})<42.35 which is an orderof magnitude deeper than previous z~6 [OIII] LFs based on JWST slitlessspectroscopy. This LF is well fit by a power law with a faint-end slope of\alpha=-2.07^{+0.22}_{-0.23}. There is little or no evolution between this LFand published [OIII] LFs at redshifts 3<~ z<~7, and no evidenceof a turnover at faint luminosities. The sizes of these extreme [OIII] emittersare broadly similar to their low redshift counterparts, the green peas. Theluminosity function of [OIII] emitters matches that of Lyman-\alpha at thebright end, suggesting that many of them should be Lyman-\alpha emitters.