| Abstract: The reionization of the Universe was largely driven by galaxies undergoing intense bursts of star formation. To explore the galaxies responsible for reionization, we combine recent JWST observations with the cosmological simulation EAGLE, specifically at redshifts greater than 6. We find that an interesting population of galaxies with high specific star formation rates and UV magnitudes brighter than -17, primarily located in halos of a billion solar masses or heavier, are efficient ionizing sources. We further develop models for the escape fraction of ionizing photons, which are best described by a skewed Gaussian function, with a flat tail toward the higher mass end. We incorporate these models into the 21cmFAST code to simulate the evolution of reionization, and the resulting ionized fraction closely matches observational data. Additionally, we compute brightness, spin, and kinetic temperatures, along with their spatial fluctuations, to gain deeper insights into reionization dynamics. A key prediction from our study is a peak in the 21 cm power spectrum at 180 MHz, corresponding to a redshift of about 6.8, which is within the observational reach of the upcoming Square Kilometre Array. Our findings also enable a deeper understanding of the star formation and its efficiency in pre-reionization galaxies detected by the JWST.
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