On the detection of the electromagnetic counterparts from lensed gravitational wave events by binary neutron star mergers

ABSTRACT Future ground-based gravitational wave (GW) detectors, i.e. Einstein telescope (ET) and Cosmic Explorer (CE), are expected to detect a significant number of lensed binary neutron star (BNS) mergers, which may provide unique tool probe cosmology. In this paper, we investigate the detectability optical/infrared electromagnetic (EM) counterparts (kilonovae/afterglows) from these BNS mergers by future GW detectors EM telescopes using simple kilonova, afterglow, lens models. ET CE ${\sim}5.32^{+26.1}_{-5.10}$ $67.3^{+332}_{-64.7}$ per year. We find that associated with all will be detectable an sky-survey in H band limiting magnitude mlim ≳ 27, while fraction is ${\lesssim}0.4{{\ \rm per\ cent}}$ g/z if ≲ 24. Generally, it more efficient search adopting infrared bands than optical/UV same mlim. like Vera C. Rubin Observatory, China Space Station Telescope, Euclid can hardly even one merger. Roman Telescope (RST) James Webb (JWST) have capability about few or such events Moreover, time delays separations between image pairs typically ranges minutes months 0.1 1 arcsec, suggesting both images most well resolved not only CE/ET domain but also RST/JWST spatially.