On the offset of the DM cusp and the interpretation of the 130 GeV line as a DM signal

TL;DR

The paper argues that the dark matter cusp needed to explain the 130 GeV gamma-ray excess cannot persist if offset from the Galactic center due to tidal forces, challenging the DM interpretation.

Contribution

It demonstrates that the offset of the DM cusp from the Galactic center makes the DM explanation of the gamma-ray line unlikely.

Findings

DM cusp cannot survive tidal forces if offset by ~1.5°

DM explanation for 130 GeV line is challenged by cusp offset

Tidal effects weaken the DM signal hypothesis

Abstract

We show that the cusp in the dark matter (DM) distribution required to explain the recently found excess in the gamma-ray spectrum at energies ~130 GeV in terms of the DM annihilations cannot survive the tidal forces if it is offset by ~1.5^\circ from the Galactic centre as suggested by observations.