Speaker
Description
The landmark multi-messenger observations of the binary neutron star (BNS) merger GW170817 provided firm evidence that such mergers can produce short gamma-ray bursts (sGRBs). However, the scarcity of BNS detections in recent gravitational-wave (GW) observing runs raises a critical question: are BNS merger rates high enough to account for the full population of observed sGRBs?
We address this question by analyzing 64 BNS population synthesis models against 16 years of Fermi-GBM data. By simulating synthetic sGRB catalogs under various jet scenarios, including GW170817-calibrated structured jets and non-universal geometries, we constrain physically viable BNS properties. We demonstrate that population models predicting low local BNS merger rates ($R_{\text{BNS}}(0) \lesssim 50 \,\text{Gpc}^{-3}\,\text{yr}^{-1}$) fail to reproduce the observed sGRB population. Reconciling these low-rate models requires either non-physical jet launching efficiencies or unrealistically wide jet opening angles ($\theta_c \gtrsim 15^\circ$) that contradict afterglow constraints. We find that models with local rates of $\approx 100 \,\text{Gpc}^{-3}\,\text{yr}^{-1}$ successfully reconcile sGRB observations with realistic jet physics.
Within these constraints, we leverage our framework to forecast multi-messenger opportunities of the coming decades. Using our physics-informed BNS catalogues, we will show specific event rate predictions in the MeV and afterglow regimes for upcoming missions (THESEUS, Crystal Eye, GRINTA). We will discuss the joint detection capabilities of these electromagnetic facilities when paired with the Advanced LIGO, Cosmic Explorer, and Einstein Telescope GW networks.
Ultimately, in this talk we will highlight how an end-to-end interface between theoretical population modeling and observational strategies enables consistent, physics-informed multi-messenger predictions for future facilities.
