Indirect searches of dark matter

TL;DR

This paper introduces a novel, model-independent method using response functions to constrain decaying dark matter models based on radio, gamma-ray, and positron observations, and explores anisotropy analysis of full-sky radio emissions.

Contribution

It presents a new response function framework for constraining dark matter decay models that is independent of specific decay spectra and discusses anisotropy analysis for dark matter detection.

Findings

Response functions allow simple constraints on dark matter decay parameters.

Angular power spectrum analysis can distinguish dark matter signals from astrophysical backgrounds.

Optimal detection window identified at GHz frequencies with specific angular scales.

Abstract

If dark matter decays or annihilates into electrons and positrons, it can affect radiation and cosmic-ray backgrounds. We review a novel, more general analysis of constraints on decaying dark matter models, by introducing the response functions based on the current radio, gamma-ray and positron observations. Constraints can be simply obtained by requiring the convolution of the response functions with actual decay spectrum of electrons and positrons smaller than the product of decay lifetime in 10^{26}s and mass in 100GeV. The response functions just depend on the astrophysical inputs such as the propagation model, but not on the microscopic decay scenario. Moreover, an anisotropy analysis of the full-sky radio emissions to identify the extragalactic dark matter annihilation is shown. We discuss the angular power spectra of the cosmological synchrotron emission from dark matter annihilations into electron positron pairs and compare them with astrophysical backgrounds and Galactic foregrounds. We find that the angular power spectrum of radio fluxes at around GHz frequencies and in the range of 200 <l <3000 opens a optimal window to disentangle the dark matter signals from common astrophysical backgrounds.