Compton scattering

Cosmology

Galaxy

Nuclear physics

Weakly interacting massive particles

Gamma ray

Astrophysics

Scalar field dark matter

Dark energy

Physics

Astronomy

Halo

Warm dark matter

Electron

Hot dark matter

Dark matter

Light dark matter

Fermi Gamma-ray Space Telescope

Journal of Cosmology and Astroparticle Physics

If the dark matter is unstable, the decay of these particles throughout the universe and in the halo of the Milky Way could contribute significantly to the isotropic gamma-ray background (IGRB) as measured by Fermi. In this article, we calculate the high-latitude gamma-ray flux resulting from dark matter decay for a wide range of channels and masses, including all contributions from inverse Compton scattering and accounting for the production and full evolution of cosmological electromagnetic cascades. We also make use of recent multi-wavelength analyses that constrain the astrophysical contributions to the IGRB, enabling us to more strongly restrict the presence any component arising from decaying dark matter. Over a wide range of decay channels and masses (from GeV to EeV and above), we derive stringent lower limits on the dark matter's lifetime, generally in the range of τ ∼ (1–5)× 1028 s.}

Constraints on decaying dark matter from the isotropic gamma-ray background