Dark matter annihilation in ω Centauri: Astrophysical implications derived from the MWA radio data

Abstract

We present an analysis of Murchison Widefield Array radio telescope data from Cen, possibly a stripped dwarf spheroidal galaxy core captured by our Galaxy. Recent interpretations of Fermi-LAT -ray data by Brown et al. (2019) and Reynoso-Cordova et al. (2019) suggest that Cen may contain significant Dark Matter. We utilize their best-fit Dark Matter annihilation models, and an estimate of the magnetic field strength in Cen, to calculate the expected radio synchrotron signal from annihilation, and show that one can usefully rule out significant parts of the magnetic field–diffusion coefficient plane using our current observational limits on the radio emission. Improvement by a factor of 10–100 on these limits could constrain the models even more tightly.