Probing dark matter decay and annihilation with Fermi LAT observations of nearby galaxy clusters
- National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China)
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22603 Hamburg (Germany)
- Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany)
Galaxy clusters are promising targets for indirect dark matter searches. Gamma-ray signatures from the decay or annihilation of dark matter particles inside these clusters could be observable with the Fermi Large Area Telescope (LAT). Based on three years of Fermi LAT gamma-ray data, we analyze the flux coming from eight nearby clusters individually as well as in a combined likelihood analysis. Concentrating mostly on signals from dark matter decay, we take into account uncertainties of the cluster masses as determined by X-ray observations and model the cluster emission as extended sources. Searching for different hadronic and leptonic decay and annihilation spectra, we do not find significant emission from any of the considered clusters and present limits on the dark matter lifetime and annihilation cross-section. We compare our lifetime limits derived from cluster observations with the limits that can be obtained from the extragalactic gamma-ray background (EGBG), and find that in case of hadronic decay the cluster limits become competitive at dark matter masses below a few hundred GeV. In case of leptonic decay, however, galaxy cluster limits are stronger than the limits from the EGBG over the full considered mass range. Finally, we show that in presence of dark matter substructures down to 10{sup −6} solar masses the limits on the dark matter annihilation cross-section could improve by a factor of a few hundred, possibly going down to the thermal cross-section of 3 × 10{sup −26}cm{sup 3}s{sup −1} for dark matter masses ∼<150GeV and annihilation into b b-bar . As a direct application of our results, we derive limits on the lifetime of gravitino dark matter in scenarios with R-parity violation. Implications of these limits for the possible observation of long-lived superparticles at the LHC are discussed.
- OSTI ID:
- 22279733
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2012, Issue 01; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
Reconstructing WIMP properties through an interplay of signal measurements in direct detection, Fermi-LAT, and CTA searches for dark matter
Gamma-ray boxes from axion-mediated dark matter