Spectral and spatial variations of the diffuse gamma-ray background in the vicinity of the Galactic plane and possible nature of the feature at 130 GeV

TL;DR

This study analyzes the spatial and spectral variations of the diffuse gamma-ray background near the Galactic plane at 20-200 GeV, questioning the interpretation of the 130 GeV feature as a dark matter signal.

Contribution

It demonstrates that the 130 GeV spectral feature varies with sky direction and may originate from background or instrumental effects, challenging its previous association with dark matter.

Findings

Spectral features vary with sky position.

The 130 GeV feature is likely not a gamma-ray line.

Background or instrumental origins are plausible.

Abstract

We study the properties of the diffuse gamma-ray background around the Galactic plane at energies 20 -- 200 GeV. We find that the spectrum of this emission possesses significant spacial variations with respect to the average smooth component. The positions and shapes of these spectral features change with the direction on the sky. We therefore argue, that the spectral feature around 130 GeV, found in several regions around the Galactic Center and in the Galactic plane in [1203.1312, 1204.2797, 1205.1045, 1206.1616], can not be interpreted with confidence as a gamma-ray line, but may be a component of the diffuse background and can be of instrumental or astrophysical origin. Therefore, the dark matter origin of this spectral feature becomes dubious.