New Perspectives for Multifrequency GW Astronomy: Strong Gravitational Lensing of GW

Direct detection of gravitational waves was for a long time the holy grail observational astronomy. The situation changed in 2015 with first registration wave signal (GW150914) by laboratory interferometers on Earth. Now, successful operating runs LIGO/Virgo detectors, resulting numerous observations signals from coalescing double compact objects (mainly binary black hole mergers) evidence neutron star system, has elevated multimessenger astronomy to an unprecedented stage. Double (binary systems, mixed hole–neutron and systems) are main targets future ground-based space-borne opening possibility multifrequency studies yielding very rich statistics such sources. This, turn, makes it possible that certain, non-negligible amounts will have chance being strongly lensed. In this paper, we discuss new perspectives detections case strong lensing. First, expected rates lensed be presented. Multifrequency events demand different treatments at frequencies, i.e., approach vs. geometric optics approach. New possibilities emerging also discussed.