Possible interaction between baryons and dark-matter particles revealed
Another article on about the same subject from the non paywalled section of Nature<p><a href="https://www.nature.com/articles/d41586-018-02616-8" rel="nofollow">https://www.nature.com/articles/d41586-018-02616-8</a><p>It's more about the light from the first stars but it explains why the signal hints to light and cool dark matter.