Searching for the radio remnants of short duration gamma-ray bursts

Understand

Neutron star mergers produce a substantial amount of fast-moving ejecta, expanding outwardly for years after the merger.

• The interaction of these ejecta with the surrounding medium may produce a weak isotropic radio remnant, detectable in relatively nearby events.
• We use late-time radio observations of short duration gamma-ray bursts (sGRBs) to constrain this model.
• Two samples of events were studied: four sGRBs that are possibly in the local (<200 Mpc) universe were selected to constrain the remnant non-thermal emission from the sub-relativistic ejecta, whereas 17 sGRBs at cosmological distances were used to constrain the presence of a proto-magnetar central engine, possibly re-energezing the merger ejecta.