Speaker
Description
The 21-cm signal is emerging as a powerful cosmological probe of dark matter. However, constraints derived from heating-based signatures are subject to significant astrophysical uncertainties, which depend sensitively on the choice of fiducial model. We illustrate this in the context of accreting primordial black holes with masses in the range $1-10^{3}$ M$_\odot$, showing how changes in poorly constrained astrophysical parameters can weaken the expected signal, and thus constraints.
To address this challenge, we introduce a novel mechanism by which dark matter can boost the 21-cm signal through the production of exotic Lyman-α photons. This channel offers a potentially more robust avenue for constraining dark matter models, as it is less degenerate with standard astrophysical processes. We discuss the implications of this channel for upcoming 21-cm experiments, and the broader prospects for using the 21-cm line as a robust dark matter probe.