Decaying dark matter in dwarf spheroidal galaxies: Prospects for X-ray and gamma-ray telescopes

Abstract

Dwarf spheroidal galaxies are dark matter dominated systems, and as such, ideal for indirect dark matter searches. If dark matter decays into high-energy photons in the dwarf galaxies, they will be a good target for current and future generations of X-ray and gamma-ray telescopes. By adopting the latest estimates of density profiles of dwarf galaxies in the Milky Way, we revise the estimates dark matter decay rates in dwarf galaxies; our results are more robust, but weaker than previous estimates. Applying these results, we study the detectability of dark matter decays with X-ray and very-high-energy gamma-ray telescopes, such as eROSITA, XRISM, Athena, HAWC, and CTA. Our projection shows that all of these X-ray telescopes will be able to critically assess the claim of the 7 keV sterile neutrino decays from stacked galaxy clusters and nearby galaxies. For TeV decaying dark matter, we can constrain its lifetime to be longer than $\sim$10${}^{27}$-10${}^{28}$ s. We also make projections for future dwarf galaxies that would be newly discovered with the Vera Rubin Observatory Legacy Survey of Space and Time, which will further improve the expected sensitivity to dark matter decays both in the keV and PeV mass ranges.

18 pages, 15 figures; comments welcome

References in corpus (10)

• The eROSITA X-ray telescope on SRG
• Weak Corrections are Relevant for Dark Matter Indirect Detection
• Dwarf galaxy annihilation and decay emission profiles for dark matter experiments
• Discovery of a 3.5 keV line in the Galactic Center and a Critical Look at the Origin of the Line Across Astronomical Targets
• New Constraints on Sterile Neutrino Dark Matter from $NuSTAR$ M31 Observations
• The observation of the Crab Nebula with LHAASO-KM2A for the performance study
• Hitomi constraints on the 3.5 keV line in the Perseus galaxy cluster
• An X-ray Spectroscopic Search for Dark Matter in the Perseus Cluster with Suzaku
• Searches for sterile neutrinos and axionlike particles from the Galactic halo with eROSITA
• EBIT Observation of Ar Dielectronic Recombination Lines Near the Unknown Faint X-Ray Feature Found in the Stacked Spectrum of Galaxy Clusters

Cited by in corpus (12)

• Strong constraints on decay and annihilation of dark matter from heating of gas-rich dwarf galaxies
• Warm Dark Matter Constraints Using Milky-Way Satellite Observations and Subhalo Evolution Modeling
• Searches for sterile neutrinos and axionlike particles from the Galactic halo with eROSITA
• A new life for sterile neutrino dark matter after the pandemic
• Axion Dark Matter from Lepton flavor-violating Decays
• Probing self-interacting sterile neutrino dark matter with the diffuse supernova neutrino background
• Search for heavy dark matter from dwarf spheroidal galaxies: leveraging cascades and subhalo models
• Unlocking Discovery Potential for Decaying Dark Matter and Faint X-ray Sources with XRISM
• Searching for Particle Dark Matter with eROSITA Early Data
• Milky Way Satellite Census. IV. Constraints on Decaying Dark Matter from Observations of Milky Way Satellite Galaxies
• Sterile neutrino Dark Matter in the minimal Dirac Seesaw
• Broken Expectations: The Effects of Modelling Assumptions on the Inferred Dark Matter Distribution in the Milky Way's Satellites