Searching for post-merger GWs in GRBs using the Cross-Correlation Algorithm (CoCoA)

The multi-messenger detection of the binary neutron star merger GW170817 and its associated gamma-ray burst (GRB) 170817a marked a significant milestone, yet questions persist regarding the nature of the compact merger remnant serving as the GRB central engine. Indeed, the properties of the electromagnetic emission associated with GW170817 suggest that a short-lived neutron star was formed after the merger, disfavoring a prompt black hole formation. Observations of cosmological GRBs with X-ray plateaus have also independently suggested the possible existence of long-lived magnetar central engines in GRBs. Hence, multi-messenger studies of the post-GRB phase may open a new avenue for shedding light on the nature of the merger remnant. In this context, we present an analysis aiming to enhance the computational efficiency of the Cross-Correlation Algorithm (CoCoA), a template-based cross-correlation technique developed to hunt for long-duration GW signals in LIGO data. We conclude our discussion highlighting detection prospects for CoCoA analyses using data from ground-based detectors of next generation.