Lighting Up Reionization through a Multi-Line Perspective

by Dr. Sarah Libanore

BGU

at Astrophysics and Cosmology Seminar

Wed, 05 Nov 2025, 11:10
Sacta-Rashi Building for Physics (54), room 207

Abstract

The Epoch of Reionization (EoR) marks the final phase transition in our Universe, as the hydrogen in the intergalactic medium evolves from cold and neutral to hot and ionized. While current observations constrain its endpoint and duration, and JWST is pushing detections to higher redshifts, large uncertainties remain.
Line Intensity Mapping (LIM) offers a powerful complementary probe by capturing the cumulative emission from both bright and faint galaxies. Investigating its applications is especially timely with the recent launch of SPHEREx, the first mission to feature multi-line LIM among its primary science goals, and with the ground-based interferometers HERA and LOFAR increasing their sensitivity and already setting upper limits on the 21-cm power spectrum.
In this talk, I will show how cross-correlations between star-forming lines and the 21-cm signal can reveal the physics of the EoR, transitioning from positive at early times to negative as ionized bubbles grow. I will also present a novel estimator sensitive to ionized fractions of ≈1-10%, the first capable of providing a model-robust signature of the EoR onset. Detecting this feature would offer a firm observational anchor for reionization, yielding unprecedented insights into early galaxy formation and the dawn of cosmic structure.

Created on 03-11-2025 by Zitrin, Adi (zitrin)
Updaded on 03-11-2025 by Zitrin, Adi (zitrin)