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arXiv · 2606.28482

Strongest constraints on dark acoustic oscillations from the Lyman-alpha forest

Zhihan Yuan·Caleb Gemmell·Keir K. Rogers·Jared Barron·Sandip Roy·David Curtin·Norman Murray
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Abstract

We set the first constraints on a small-scale dark acoustic oscillation (DAO) in the linear matter power spectrum arising from dark sector interactions, with a full forward model of the Ly-$\alpha$ forest. No more than 30\% of dark matter can form DAOs if they peak at wavenumbers $< 50\,h\,\mathrm{Mpc}^{-1}$ (95\% c.l.), probing scales $25 \times$ smaller than the cosmic microwave background (CMB). Given the complex covariance of DAO and nuisance parameters, we use a deep kernel learning emulator of hydrodynamical simulations to capture imprints of linear oscillations in the Ly-$\alpha$ forest.

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Zhihan Yuan, Caleb Gemmell, Keir K. Rogers, Jared Barron, Sandip Roy, David Curtin, Norman Murray. 2026-06-26. Strongest constraints on dark acoustic oscillations from the Lyman-alpha forest. https://arxiv.org/abs/2606.28482

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