Joint constraints on thermal relic dark matter from strong gravitational lensing, the Ly α forest, and Milky Way satellites

Enzi, Wolfgang; Murgia, Riccardo; Newton, Oliver; Vegetti, Simona; Frenk, Carlos; Viel, Matteo; Cautun, Marius; Fassnacht, Christopher D; Auger, Matt; Despali, Giulia; McKean, John; Koopmans, Léon VE; Lovell, Mark

Abstract

We derive joint constraints on the warm dark matter (WDM) half-mode scale by combining the analyses of a selection of astrophysical probes: strong gravitational lensing with extended sources, the Ly α forest, and the number of luminous satellites in the Milky Way. We derive an upper limit of λhm = 0.089 Mpc h−1 at the 95 per cent confidence level, which we show to be stable for a broad range of prior choices. Assuming a Planck cosmology and that WDM particles are thermal relics, this corresponds to an upper limit on the half-mode mass of Mhm < 3 × 107 M⊙ h−1, and a lower limit on the particle mass of mth > 6.048 keV, both at the 95 per cent confidence level. We find that models with λhm > 0.223 Mpc h−1 (corresponding to mth > 2.552 keV and Mhm < 4.8 × 108 M⊙ h−1) are ruled out with respect to the maximum likelihood model by a factor ≤1/20. For lepton asymmetries L6 > 10, we rule out the 7.1 keV sterile neutrino dark matter model, which presents a possible explanation to the unidentified 3.55 keV line in the Milky Way and clusters of galaxies. The inferred 95 percentiles suggest that we further rule out the ETHOS-4 model of self-interacting DM. Our results highlight the importance of extending the current constraints to lower half-mode scales. We address important sources of systematic errors and provide prospects for how the constraints of these probes can be improved upon in the future.

Citation

Enzi, W., Murgia, R., Newton, O., Vegetti, S., Frenk, C., Viel, M., Cautun, M., Fassnacht, C. D., Auger, M., Despali, G., McKean, J., Koopmans, L. V., & Lovell, M. (2021). Joint constraints on thermal relic dark matter from strong gravitational lensing, the Ly α forest, and Milky Way satellites. Monthly Notices of the Royal Astronomical Society, 506(4), 5848-5862. https://doi.org/10.1093/mnras/stab1960

• Journal Article Type: Article
• Acceptance Date: Jun 29, 2021
• Online Publication Date: Jul 10, 2021
• Publication Date: 2021
• Deposit Date: Nov 15, 2021
• Publicly Available Date: Nov 15, 2021
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 506
• Issue: 4
• Pages: 5848-5862
• DOI: https://doi.org/10.1093/mnras/stab1960
• Public URL: https://durham-repository.worktribe.com/output/1224935