Constraints on the dark matter annihilation scenario of Fermi 130 GeV $\gamma$-ray line emission by continuous gamma-rays, Milky Way halo, galaxy clusters and dwarf galaxies observations

TL;DR

This study uses Fermi data to test dark matter annihilation as the source of the 130 GeV gamma-ray line, finding strong constraints on continuous emission and no conclusive line signals from other sources.

Contribution

It provides comprehensive constraints on dark matter annihilation models using multiple astrophysical observations, challenging the dark matter explanation for the 130 GeV gamma-ray line.

Findings

Strong limits on continuous gamma-ray emission from the Galactic center.

No detection of line emission from the Galactic halo, clusters, or dwarf galaxies.

Possible photon concentration in clusters around 120-140 GeV, but with weak constraints.

Abstract

It was recently reported that there may exist monochromatic $\gamma$-ray emission at $\sim 130$ GeV from the Galactic center in the Fermi Large Area Telescope data, which might be related with dark matter (DM) annihilation. In this work we carry out a comprehensive check of consistency of the results with the DM annihilation scenario, using the 3.7 yrs Fermi observation of the inner Galaxy, Galactic halo, clusters of galaxies and dwarf galaxies. The results found are as follows. 1) Very strong constraints on the DM annihilation into continuous $\gamma$-rays from the Galactic center are set, which are as stringent as the "natural" scale assuming thermal freeze-out of DM. Such limit sets strong constraint on the DM models to explain the line emission. 2) No line emission from the Galactic halo is found in the Fermi data, and the constraints on line emission is marginally consistent with the DM annihilation interpretation of the $\sim 130$ GeV line emission from the inner Galaxy. 3) No line emission from galaxy clusters and dwarf galaxies is detected, although possible concentration of photons from clusters in 120-140 GeV is revealed. The constraints from clusters and dwarf galaxies are weak and consistent with the DM annihilation scenario to explain the $\sim 130$ GeV line emission.