Probing the Era of Reionization with Lyman-alpha Observations

Intae Jung (NASA GSFC)
Friday, November 12, 2021 - 2:00pm to 3:00pm

Lyman-alpha emission has played a pivotal role in constraining the neutral hydrogen (HI) fraction of the IGM during the epoch of reionization thanks to the resonant nature of Lyman-alpha scattering with HI. Initial Lyman-alpha studies of multi-object spectroscopy (MOS) have shown decreasing Lyman-alpha emission from z ~ 6 to 7, which implies an increasing IGM HI fraction. Furthermore, with a rapid increase of collected galaxy spectra over a wide field, recent Lyman-alpha studies have revealed significant spatial variation in the IGM HI fraction, indicating inhomogeneity in reionization. Combining the HST slitless grism data and the Keck multi-slit spectroscopic data, we analyze spectra of 275 z ~ 6 - 8 galaxies to investigate Lyman-alpha transmission in the IGM depending on galaxy UV luminosities. I will present the results of the spectroscopic analysis, which imply that reionization proceeds more rapidly and/or earlier around UV brighter galaxies. I will also discuss future studies for improving the use of Lyman-alpha as a probe of reionization.

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