Cake Talk by Xiangyu Jin
Understanding when and how reionization happened is crucial for studying the early structure formation and the properties of first galaxies in the Universe. High-redshift quasars have been playing important roles in constraining the timing and topology of reionization. At z>5.5, the observed IGM Lyman alpha forest optical depth, imprinted in high-redshift quasar spectra, shows a significant scatter, indicating an inhomogeneous reionization process. However, the nature of the inhomogeneous reionization, whether it is dominated by the large-scale fluctuations in the ionizing background or in the IGM temperature, remains unclear. In this talk, I will introduce recent constraints on the timing and topology of reionization from ground-based observations of high-redshift quasars and I will present the early results of IGM transmission around [OIII] emitters detected in JWST ASPIRE quasar fields. I will discuss their constraints on reionization models and the implications on the origins of the inhomogeneity of reionization process.