Lyman-$\alpha$ limit on axion-like cold dark matter

TL;DR

This paper establishes new constraints on axion-like particle dark matter using Lyman-alpha data, significantly narrowing the viable mass range and complementing existing bounds from other astrophysical observations.

Contribution

It provides the most stringent Lyman-alpha based limits on ALP dark matter in the 375-425 eV mass range and combines these with other bounds to refine exclusion regions.

Findings

New Lyman-alpha limits exclude ALP masses around 375-425 eV.

Combined bounds tighten constraints on ALP dark matter models.

Results are complementary to existing Leo T and X-ray bounds.

Abstract

Using low redshift data on astrophysical reionization, we report new Lyman-$\alpha$ limit on axion-like particle (ALP) as cold dark matter in ALP mass range of $m_{a}\sim 30-1000$ eV. Compared to the Leo T and soft-X ray bound, this limit is so far the most stringent in the ALP mass range of $m_{a}\sim 375-425$ eV and complementary in the ALP mass range otherwise. Combing these limits, we show new exclusion limits on $m_a$ for the ALP DM from either misalignment or freeze-in mechanism.