English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The detection of gamma-rays from dark matter (DM) annihilation is among thescientific goals of the Fermi Large Area Telescope (formerly known as GLAST)and Cherenkov telescopes. In this paper we investigate the existence ofrealistic chances of such a discovery selecting some nearby dwarf spheroidalgalaxies (dSph) as a target. We study the detectability with the Fermi-LAT ofthe gamma-ray flux from DM annihilation in Draco, Ursa Minor, Carina, andSextans, for which the state-of-art DM density profiles were available. Weassume the DM is made of Weakly Interacting Massive Particles such as theLightest Supersymmetric Particle (LSP) and compute the expected gamma-ray fluxfor optimistic choices of the unknown underlying particle physics parameters.We then compute the boost factors due to the presence of DM clumps and of acentral supermassive black hole. Finally, we compare our predictions with theFermi-LAT sensitivity maps. We find that the dSph galaxies shine above theGalactic smooth halo: e.g., the Galactic halo is brighter than the Draco dSphonly for angles smaller than 2.3 degrees above the Galactic Center. We alsofind that the presence of a cusp or a constant density core in the DM massdensity profile does not produce any relevant effect in the gamma-ray flux dueto the fortunate combination of the geometrical acceptance of the Fermi-LATdetector and the distance of the galaxies and that no significant enhancementis given by the presence of a central black hole or a population ofsub-subhalos. We conclude that, even for the most optimistic scenario ofparticle physics, the gamma-ray flux from DM annihilation in the dSph galaxiesof the LG would be too low to be detected with the Fermi-LAT.

Could the Fermi-LAT detect gamma-rays from dark matter annihilation in the dwarf galaxies of the Local Group?