Predicting the XRISM dark matter decay signal in the Milky Way halo

Lovell, M R

Abstract

Dark matter may be detected in X-ray decay, including from the decay of the dark matter particles that make up the Milky Way (MW) halo. We use a range of density profiles to compute X-ray line intensity profiles, with a focus on the resonantly produced sterile neutrino dark matter candidate. Compared to the Navarro–Frenk–White density profile, we show that using an adiabatically contracted halo profile suppresses the line intensity in the halo outskirts and enhances it in the Galactic Centre (GC), although this enhancement is eliminated by the likely presence of a core within 3 kpc. Comparing our results to MW halo observations, other X-ray observations, and structure formation constraints implies a sterile neutrino mixing angle parameter s11 ≡ sin 2(2θ) × 1011 ∼ [3, 4] (particle lifetime
⁠), which is nevertheless is strong tension with some reported non-detections. We make predictions for the likely decay flux that the X-Ray Imaging and Spectroscopy Mission (XRISM) satellite would measure in the GC, plus the Virgo and Perseus clusters, and outline further steps to determine whether the dark matter is indeed resonantly produced sterile neutrinos as detected in X-ray decay.

Citation

Lovell, M. R. (2024). Predicting the XRISM dark matter decay signal in the Milky Way halo. Monthly Notices of the Royal Astronomical Society, 529(4), 4050-4055. https://doi.org/10.1093/mnras/stae775

• Journal Article Type: Article
• Acceptance Date: Mar 12, 2024
• Online Publication Date: Mar 23, 2024
• Publication Date: 2024-04
• Deposit Date: May 15, 2024
• Publicly Available Date: May 15, 2024
• 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: 529
• Issue: 4
• Pages: 4050-4055
• DOI: https://doi.org/10.1093/mnras/stae775
• Public URL: https://durham-repository.worktribe.com/output/2441124