Research
My research is organized around three connected questions: when and how did reionization end, how are galaxies connected to IGM opacity, and how do galaxies and quasars reshape their surroundings?
When and how did reionization end?
Reionization transformed the intergalactic medium from mostly neutral to mostly ionized during the first billion years. I use quasar absorption spectra and deep JWST imaging to measure IGM opacity, ionizing-photon mean free paths, and high-order Lyman-series absorption near the end of this transition. These observations test whether reionization ended sharply by redshift six, or whether dense neutral gas and ionizing-photon sinks persisted later than expected.
How are galaxies connected to IGM opacity?
JWST now allows us to map galaxies in the same regions where we measure intergalactic absorption. I use Lyα emission, rest-frame optical lines, and galaxy environments to ask whether galaxies trace ionized bubbles, whether overdense regions are always more transparent, and how large-scale structure shapes reionization.
How do galaxies and quasars reshape their surroundings?
Galaxies and quasars do not only form from the IGM; they also change it. I study how ionizing radiation, outflows, metals, and black-hole activity propagate from galaxies into their surrounding gas, linking small-scale galaxy evolution to the large-scale state of the cosmic web.
