Internal bremsstrahlung in neutralino annihilation: revised impact on indirect detection from γ-rays

We revise the impact of internal bremsstrahlung photons in the context of the constrained minimal supersymmetric standard model on γ-ray dark matter annihilation searches. As an example, we review the γ-ray dark matter detection prospects from Draco dwarf spheroidal galaxy at the MAGIC stereoscopic system and the CTA project. We find that for a typical energy threshold of 100 GeV the flux of high energy photons is enhanced by an order of magnitude in the stau coannihilation region, where the signal remains still at least three orders of magnitude below the sensitivity of the instruments. However, the effect of internal bremsstrahlung is negligible or small in more optimistic scenarios for detection like the funnel and focus point regions.