The impact of propagation uncertainties on the potential Dark Matter contribution to the Fermi LAT mid-latitude gamma-ray data

TL;DR

This study assesses how uncertainties in cosmic ray propagation affect gamma-ray flux estimates in the mid-latitude region, exploring the impact of astrophysical backgrounds, extragalactic sources, and potential dark matter contributions on Fermi LAT data analysis.

Contribution

It introduces a comprehensive analysis of propagation uncertainties and their influence on gamma-ray flux modeling, including the potential role of neutralino dark matter in fitting Fermi LAT data.

Findings

Propagation uncertainties can dominate gamma-ray flux estimates by 1-2 orders of magnitude.

Fitting spectral normalizations reduces uncertainties to less than an order of magnitude.

Including a dark matter component improves fits and suggests possible dark matter signals.

Abstract

We investigate the extent to which the uncertainties associated with the propagation of Galactic cosmic rays impact upon estimates for the gamma-ray flux from the mid-latitude region. We consider contributions from both standard astrophysical background (SAB) processes as well as resolved point sources. We have found that the uncertainties in the total gamma-ray flux from the mid-latitude region relating to propagation parameter values consistent with local B/C and Be10/Be9 data dominate by 1-2 orders of magnitude. These uncertainties are reduced to less than an order of magnitude when the normalisations of the SAB spectral components are fitted to the corresponding Fermi LAT data. We have found that for many propagation parameter configurations (PPCs) our fits improve when an extragalactic background (EGB) component is simultaneously fitted to the data. We also investigate the improvement in our fits when a flux contribution from neutralino dark matter (DM), described by the Minimal Supersymmetric Standard Model, was simultaneously fitted to the data. We consider three representative cases of neutralino DM for both Burkert and Einasto DM density profiles, in each case simultaneously fitting a boost factor of the DM contribution together with the SAB and EGB components. We have found that for several PPCs there are significant improvements in our fits, yielding both substantial EGB and DM components, where for a few of these PPCs the best-fit EGB component is consistent with recent estimates by the Fermi Collaboration.