Constraining Dark Matter with the Lyman-alpha Flux Power Spectrum

by Dr Laura Sagunski (York University, Canada)

Thursday 19 Oct 2017, 11:15 → 12:15 Europe/Berlin

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Although dark matter plays a fundamental role in the formation of structures in the Universe, its particle nature is still unknown. Important constraints on the nature of dark matter arise from cosmological probes, such as the cosmic microwave background. Another probe that can be used to constrain the properties of dark matter is the one-dimensional Lyman-$\alpha$ flux power spectrum, as for instance measured by the Baryon Oscillation Spectroscopic Survey (BOSS). However, to extract valuable constraints from the data, accurate theoretical predictions for the Lyman-$\alpha$ flux power spectrum are needed. Motivated by this, we develop a theoretical approach to compute the Lyman-$\alpha$ flux power spectrum from first principles and for different dark matter models. In our approach, we express the Lyman-$\alpha$ flux power spectrum in terms of the non-linear matter power spectrum, in which the dark matter physics is encoded, and an effective distortion kernel. To determine the non-linear matter power spectrum, we work in the framework of non-relativistic cosmological perturbation theory and apply a perturbative method that relies on viscous fluid dynamics. Finally, we use our theoretical approach for the Lyman-$\alpha$ flux power spectrum to fit the BOSS data.