Secondary radiation from the Pamela/ATIC excess and relevance for Fermi

TL;DR

This paper investigates secondary radiation signals from electron/positron excesses observed by Pamela and ATIC, focusing on Inverse Compton Scattering signatures that could confirm or refute dark matter interpretations with Fermi data.

Contribution

It highlights the potential of ICS radiation, especially the 'ICS Haze', as a robust indicator to distinguish dark matter signals from astrophysical sources in gamma-ray observations.

Findings

ICS radiation shows tension with EGRET data under WIMP annihilation models.

Fermi data can confirm or exclude dark matter scenarios within a year.

The 'ICS Haze' is a distinctive feature that can differentiate between dark matter and astrophysical origins.

Abstract

The excess of electrons/positrons observed by the Pamela and ATIC experiments gives rise to a noticeable amount of synchrotron and Inverse Compton Scattering (ICS) radiation when the e^+e^- interact with the Galactic Magnetic Field, and the InterStellar Radiation Field (ISRF). In particular, the ICS signal produced within the WIMP annihilation interpretation of the Pamela/ATIC excess shows already some tension with the EGRET data. On the other hand, 1 yr of Fermi data taking will be enough to rule out or confirm this scenario with a high confidence level. The ICS radiation produces a peculiar and clean "ICS Haze" feature, as well, which can be used to discriminate between the astrophysical and Dark Matter scenarios. This ICS signature is very prominent even several degrees away from the galactic center, and it is thus a very robust prediction with respect to the choice of the DM profile and the uncertainties in the ISRF.