Synchrotron Radiation from the Galactic Center in Decaying Dark Matter Scenario

TL;DR

This paper investigates synchrotron radiation from the Galactic center caused by decaying dark matter particles, aiming to explain the PAMELA positron excess and calculating expected flux levels.

Contribution

It introduces a model of unstable, long-lived dark matter decay producing electrons and positrons, linking it to observed cosmic ray anomalies and synchrotron radiation.

Findings

Synchrotron flux is around 1 kJy/str for dark matter lifetime ~10^26 seconds.

Decaying dark matter can account for the PAMELA positron excess.

Flux levels depend on particle physics and cosmological parameters.

Abstract

We discuss the synchrotron radiation flux from the Galactic center in unstable dark matter scenario. Motivated by the anomalous excess of the positron fraction recently reported by the PAMELA collaboration, we consider the case that the dark matter particle is unstable (and long-lived), and that energetic electron and positron are produced by the decay of dark matter. Then, the emitted electron and positron becomes the source of the synchrotron radiation. We calculate the synchrotron radiation flux for models of decaying dark matter, which can explain the PAMELA positron excess. Taking the lifetime of the dark matter of O(10^26 sec), which is the suggested value to explain the PAMELA anomaly, the synchrotron radiation flux is found to be O(1 kJy/str) or smaller, depending on the particle-physics and cosmological parameters.