Abstract

Contributed Talk - Splinter LIM

Friday, 11 September 2026, 16:15   (MW-2050)

Constraining Reionization with 21cm Cross-Correlations: Galaxies and Line Intensity Mapping

Caroline Heneka
Heidelberg University

Cross-correlating 21cm intensity mapping with complementary tracers of the high-redshift Universe offers a powerful, foreground-robust window into the Epoch of Reionization (EoR), directly linking ionization morphology to the galaxy population and gaseous media driving it. In this talk, I will present results on the constraining power of 21cm–galaxy cross-correlations, using our simulation-based inference framework EoRFlow with realistic mock observations to show how survey design, including field of view, redshift precision, and minimum detectable halo mass, shapes constraints on the neutral hydrogen fraction, reionization morphology, and source properties such as escape fraction and star formation efficiency; notably, such cross-correlations break key degeneracies that limit 21cm auto-power analyses alone. I will then turn to line intensity mapping (LIM) of UV, optical, and infrared lines tracing ionized gas, presenting updated prospects for its cross-correlation with SKA-Low, and highlighting promising tracers such as the Lyman-alpha line accessible to SPHEREx and lesser-explored infrared dust lines. Together, these two cross-correlation approaches, alongside future galaxy surveys like the Nancy Grace Roman Space Telescope, point toward a synergistic path for uncovering the evolution of the IGM and the sources that reionized the Universe.