W-WIMP Annihilation as a Source of the Fermi Bubbles

TL;DR

This paper investigates whether W-WIMPs, a type of dark matter particle, can explain the gamma-ray emission observed in the Fermi Bubbles by matching their annihilation rate and relic density.

Contribution

It analyzes the potential of W-WIMPs within a minimal hidden sector model to account for Fermi Bubble gamma-ray signals and relic abundance.

Findings

W-WIMPs can produce the required gamma-ray flux.

The model can match the observed relic density.

Parameter space allows for consistent dark matter explanation.

Abstract

The Fermi Gamma-ray Space Telescope discovered two \gamma-ray emitting bubble-shaped structures that extend nearly symmetrically on either side of our Galaxy and appear morphologically connected to the Galactic center. The origin of the emission is still not entirely clear. It was recently shown that the spectral shape of the emission from the Fermi bubbles is well described by an approximately 50 GeV dark matter particle annihilating to b \bar b, with a normalization corresponding to a velocity average annihilation cross section of < \sigma_b v > ~ 8 \times 10^{-27} cm^3/s. We study the minimal hidden sector recently introduced by Weinberg and examine to what extent its weakly-interacting massive particles (W-WIMPs) are capable of accommodating both the desired effective annihilation rate into quarks and the observed relic density.