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Arxiv: Compact [OIII] emission-line regions ("Green Seeds") in \mathrm{Hα} emitters at Cosmic Noon from JWST Observations Published: 10/11/2024 7:43:57 AM Updated: 10/11/2024 7:43:57 AM

Paper abstract: We present a rest-frame optical, spatially resolved analysis of more than 100\mathrm{H\alpha} emitters (HAEs) at z~2.2 in the ZFOURGE-CDFS fieldusing NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES).The ultra-deep, high-resolution data gives us maps of the resolved emissionline regions of HAEs with stellar mass ranging from 10^{8}\,M_{\odot} to10^{10}\,M_{\odot}. An [OIII] emission-line map of each HAE is created fromthe flux excess in the F150W filter, leading to the discovery of a populationof kiloparsec-scale compact emission line regions (``Green Seeds") with highequivalent widths (\mathrm{EW}). We obtain a sample of 128 Green Seeds from68 HAEs with rest-frame \mathrm{EW_{[OIII]}}>200\r{A}. Moreover, 17 of themhave extremely large \mathrm{EW_{[OIII]}}>1000\r{A}, suggesting the possibleLyman continuum (LyC) leakage from these emission line regions. Embedded withinthe host galaxy, many Green Seeds correspond to UV star-forming clumps andH{\sc ii} regions, indicating elevated starburst activity in them, withspecific star formation rates (sSFR) several times higher than that of the hostgalaxy. Based on theoretical frameworks, Green Seeds are expected to be formedthrough gravitational disk instability and/or galaxy mergers. Considering thestellar masses of Green Seeds, we speculate that high-mass Green Seeds maymigrate toward the galactic center to build the central bulge, while low-massGreen Seeds are easily disrupted and short-lived. Besides, we propose that someGreen Seeds could be the progenitors of globular clusters or ultracompact dwarfgalaxies observed in the local universe.