Speaker
Description
We propose a novel mechanism for constraining warm dark matter (WDM) models via the so-called “memory of reionization” effect, which is that the thermal history of gas after cosmic reionization is sensitive to when the gas is reionized. The suppression of small-scale structure due to WDM affects the evolution of post-reionization gas, while thermal relics can couple to ionized bubbles at the scales of tens of Mpc. As such, the small-scale effect due to WDM can leave an imprint on the gas at large scales, which can be observed by Ly$\alpha$ forest and HI 21 cm intensity mapping. We forecast the accuracy of constraints on WDM using Ly$\alpha$ forest 3D power spectrum with DESI-like surveys, and 21 cm power spectrum with SKA1-LOW and PUMA surveys. We demonstrate that this approach can provide unprecedentedly tight constraints on WDM mass.
