Search for photon-linelike signatures from dark matter annihilations with H.E.S.S

Area of Science:

• High-energy astrophysics
• Particle cosmology
• Dark matter physics

Background:

• Dark matter (DM) particle self-annihilation or decay may produce gamma-ray line signatures in the very-high-energy (E(γ)>100 GeV) domain.
• These signals are distinguishable from continuous spectra of astrophysical sources.
• Previous studies with Fermi-LAT provided limits at lower energies.

Purpose of the Study:

• To search for and constrain dark matter annihilation or decay signals via gamma-ray line emission.
• To extend previous dark matter searches into the very-high-energy domain using H.E.S.S. data.
• To complement Fermi-LAT results by probing higher energy ranges.

Main Methods:

• Utilized data from the H.E.S.S. gamma-ray instrument.
• Analyzed observations of the central Milky Way halo and extragalactic regions.
• Searched for monochromatic gamma-ray line emission between approximately 500 GeV and 25 TeV.

Main Results:

• No statistically significant gamma-ray line signal consistent with dark matter was detected.
• Established upper limits on monochromatic gamma-ray flux for both Galactic halo and extragalactic observations.
• Derived upper limits on the velocity-averaged dark matter annihilation cross section for a 1 TeV DM particle.

Conclusions:

• The study provides stringent constraints on dark matter properties, particularly for particle masses around 1 TeV.
• The results contribute to narrowing down the parameter space for dark matter candidates.
• Future searches with enhanced sensitivity will be crucial for detecting potential dark matter signals.