Implications of High-Resolution Simulations on Indirect Dark Matter Searches

TL;DR

This paper analyzes high-resolution simulations to refine indirect dark matter detection strategies, showing that the search approach is robust despite flux normalization differences and that antimatter flux boosts are insufficient to explain recent cosmic-ray anomalies.

Contribution

It introduces a strategy to optimize dark matter detection regions based on simulation data and assesses the impact of simulation differences on detection prospects.

Findings

Detection strategy remains effective despite flux normalization differences.

Few individual dark matter clumps could be resolved with Fermi-LAT.

Boost factors for antimatter are too small to explain recent anomalies.

Abstract

We study the prospects for detecting the annihilation products of Dark Matter [DM] in the framework of the two highest-resolution numerical simulations currently available, i.e. {\it Via Lactea II} and {\it Aquarius}. We propose a strategy to determine the shape and size of the region around the Galactic center that maximizes the probability of observing a DM signal, and we show that although the predicted flux can differ by a factor of 10 for a given DM candidate in the two simulation setups, the search strategy remains actually unchanged, since it relies on the angular profile of the annihilation flux, not on its normalization. We present mock gamma-ray maps that keep into account the diffuse emission produced by unresolved halos in the Galaxy, and we estimate that in an optimistic DM scenario a few individual clumps can be resolved above the background with the Fermi-LAT. Finally we calculate the energy-dependent boost factors for positrons and antiprotons, and show that they are always of $\cal O$(1), and therefore they cannot lead to the large enhancements of the antimatter fluxes required to explain the recent PAMELA, ATIC, Fermi and HESS data.