One likelihood to bind them all: Lyman-$\alpha$ constraints on non-standard dark matter

TL;DR

This paper develops a flexible Lyman-$ ext{alpha}$ likelihood method to constrain various non-standard dark matter models, demonstrating its effectiveness on models like feebly interacting, baryon-interacting, and mixed cold+warm dark matter, with new insights into their parameter spaces.

Contribution

It introduces a versatile likelihood framework for Lyman-$ ext{alpha}$ data to test a wide range of dark matter models beyond $ ext{Λ}$CDM, including novel constraints on interactions.

Findings

Dark matter-baryon interactions show a mild preference for non-zero values.

Lyman-$ ext{alpha}$ data effectively constrain mixed cold+warm dark matter models.

The developed likelihood is robust and adaptable to various non-standard dark matter scenarios.

Abstract

Recent cosmological tensions have rekindled the search for models beyond $\Lambda$CDM that cause a suppression of the matter power spectrum. Due to the small scales accessible to Lyman-$\alpha$ data they are an excellent additional tool to probe such models. In this work we extend a recently-developed approach for using Lyman-$\alpha$ data to constrain the power spectrum suppression caused by almost any mixture of cold and non-standard dark matter. We highlight the steps involved in the development of a corresponding likelihood that will be publicly released upon publication of this work. We study three examples of models suppressing the power spectrum, namely feebly interacting dark matter, dark matter interacting with baryons, and mixed cold+warm dark matter. The latter two can be well constrained from Lyman-$\alpha$ data, and we derive novel conclusions on the cosmologically allowed parameter spaces, including finding a mild preference for non-zero interactions between dark matter and baryons. The consistency of the constraints obtained on these models highlight the robustness and flexibility of the likelihood developed here.