Observational data of GRBs

In contrast to previous approaches, our methodology simultaneously models both the afterglow and KN. We find that all GRBs in our sample have a KN, but we were unable to confirm or exclude its presence in GRB 150101B. A BNS progenitor is favored for GRB 160821B, GRB 170817A/AT2017gfo, GRB 211211A, and GRB 230307A.

For GRB 150101B and GRB 191019A, we found a slight preference for the NSBH scenario; however, a BNS is also a viable possibility. For KN emission, we see that the median wind mass <Mwind>=0.027^+0.046^_-0.019_M_{sun}_ is higher than the dynamical <Mdyn>=0.012^+0.007^_-0.006_M_{sun}_. We find that Mwind and the collimation-corrected kinetic energy of the jet can be attributed as log(Mwind)=-20.23+0.38log(E0,J).

We confirm the results of numerical simulations that the mass-weighted tidal deformability increases with decrease in the chirp mass. Our results exemplify and reinforce that EM modeling is the only feasible pathway to investigate binary mergers in absence of GW observations. In this work, we present for the first time the binary progenitor properties of a sizable sample of merger-driven GRBs.