Host galaxies and electromagnetic counterparts to binary neutron star mergers across the cosmic time: detectability of GW170817-like events

The detection of electromagnetic radiation (EM) accompanying the gravitational wave (GW) signal from binary neutron star (BNS) merger GW170817 has revealed that these systems constitute at least a fraction progenitors short gamma-ray bursts (SGRBs). As detectors keep pushing their horizons, it is important to assess coupled GW/EM probabilities, and how maximize observational prospects. Here we perform population synthesis calculations BNS evolution with code MOBSE, seed binaries in galaxies three representative redshifts (z=0.01,0.1,1) Illustris TNG50 simulation. are evolved locations numerically tracked host galactic potentials until merger. Adopting astrophysical parameters GRB170817A as prototype, compute broadband lightcurves jets mergers, afterglow brightness depending on local medium density sites. We Monte Carlo simulations resulting EM assuming either random viewing angle respect jet, or jet aligned orbital angular momentum binary, which biases probability for GW-triggered events. find ~70-80% BNSs z=0.01 should be detectable gamma-rays. probabilities mergers vary between ~0.3-0.7%, higher values momentum, comparable across high low-energy bands, unlike gamma-ray-triggered events (cosmological SGRBs) significantly brighter energies. further quantify galaxy masses.