# Constraints on dark matter annihilation in dwarf spheroidal galaxies from low frequency radio observations

## TL;DR

This study sets initial radio observational limits on dark matter annihilation signals in dwarf galaxies below 1 GHz, highlighting the potential of future low-frequency telescopes like SKA to probe dark matter properties.

## Contribution

First observational constraints on dark matter annihilation signals in dwarf spheroidal galaxies at sub-GHz radio frequencies using MWA and GMRT data.

## Key findings

- Limits do not constrain dark matter models for in-situ magnetic fields of 1 μG.
- Stronger magnetic fields could allow constraints comparable to gamma-ray and cosmic ray observations.
- Future SKA observations may significantly improve constraints on dark matter particle mass.

## Abstract

We present the first observational limits on the predicted synchrotron signals from particle Dark Matter annihilation models in dwarf spheroidal galaxies at radio frequencies below 1 GHz. We use a combination of survey data from the Murchison Widefield Array (MWA) and the Giant Metre-wave Radio Telescope (GMRT) to search for diffuse radio emission from 14 dwarf spheroidal galaxies. For in-situ magnetic fields of 1 $\mu G$ and any plausible value for the diffusion coefficient, our limits do not constrain any Dark Matter models. However, for stronger magnetic fields our data might provide constraints comparable to existing limits from gamma-ray and cosmic ray observations. Predictions for the sensitivity of the upgraded MWA show that models with Dark Matter particle mass up to $\sim$ 1.6 TeV (1 TeV) may be constrained for magnetic field of 2 $\mu G$ (1 $\mu G$). While much deeper limits from the future low frequency Square Kilometre Array (SKA) will challenge the LHC in searches for Dark Matter particles, the MWA provides a valuable first step toward the SKA at low frequencies.