Consistency of dark matter interpretations of the 3.5 keV X-ray line

Abstract

Tentative evidence of a 3.5 keV X-ray line has been found in the stacked spectra of galaxy clusters, individual clusters, the Andromeda galaxy and the galactic center, leading to speculation that it could be due to decays of metastable dark matter such as sterile neutrinos. However searches for the line in other systems such as dwarf satellites of the Milky Way have given negative or ambiguous results. We reanalyze both the positive and negative searches from the point of view that the line is due to inelastic scattering of dark matter to an excited state that subsequently decays---the mechanism of excited dark matter (XDM). Unlike the metastable dark matter scenario, XDM gives a stronger signal in systems with higher velocity dispersions, such as galaxy clusters. We show that the predictions of XDM can be consistent with null searches from dwarf satellites, while the signal from the closest individual galaxies can be detectable having a flux consistent with that from clusters. We discuss the impact of our new fits to the data for two specific realizations of XDM.

14 pages, 10 figures; v.2. corrected error in M31 field of view; main results unchanged; v.3. incorporated results from arXiv:1411.0050, improved fig. 1, added references; v.4. changed title for journal, added references, clarified role of XDM parameters; v.5. fixed typos, content matches published version

References in corpus (11)

• The Local Dark Matter Density
• Exciting Dark Matter and the INTEGRAL/SPI 511 keV signal
• Baryons at the Edge of the X-ray Brightest Galaxy Cluster
• A deep kinematic survey of planetary nebulae in the Andromeda Galaxy using the Planetary Nebula Spectrograph
• The velocity dispersion and mass profile of the Milky Way
• A 3.55 keV Photon Line and its Morphology from a 3.55 keV ALP Line
• The galactic 511 keV line from electroweak scale WIMPs
• Dark Matter CMB Constraints and Likelihoods for Poor Particle Physicists
• X-ray Lines from Dark Matter: The Good, The Bad, and The Unlikely
• 3.5 keV X-rays as the "21 cm line" of dark atoms, and a link to light sterile neutrinos
• Nonabelian dark matter models for 3.5 keV X-rays

Cited by in corpus (9)

• Self-Scattering for Dark Matter with an Excited State
• Les Houches Lectures on Indirect Detection of Dark Matter
• Non-abelian Dark Matter Solutions for Galactic Gamma-ray Excess and Perseus 3.5 keV X-ray Line
• A 3.55 keV Line from Exciting Dark Matter without a Hidden Sector
• Constraining Sterile Neutrino Dark Matter in the Milky Way Halo with Swift-XRT
• Supersymmetric Higgs-portal and X-ray lines
• Diffuse X-Ray and Gamma-Ray Limits on Boson Stars that Interact with Nuclei
• Exploring Ultralight Scalar Assistance in Sterile Neutrino Dark Matter: Cold Spectrum and Unusual X/Gamma-ray Signatures
• Structure Formation Limits on Axion-Like Dark Matter