In this paper we study gravitational lensing of gravitational wave events. The main point of the present work is to introduce a semi-analytic approach so that each ingredient can be varied and tested individually. Our analytic model for the source population is motivated by a numerical study and we compare semi-analytical and numerical results. We determine the expected magnification for events seen at a given observed luminosity distance. We find that while the probability of significant magnification of the observed LIGO-Virgo events is very small, the probability distribution of the magnification has a significant tail to high μ such that e.g. the variance of the magnification is very large and even diverges in the geometric optics approximation. For the 10 binary black hole mergers observed by LIGO-Virgo in the O1+O2 observation campaigns, the probability that one of them has been magnified with magnification of 5 or bigger is Pobs(>5)∼0.01 while the probability of magnification by 50 or bigger is Pobs(>50)∼0.005.
@article{arxiv.1912.11916,
title = {Strong and weak lensing of Gravitational Waves: a semi-analytical approach},
author = {Giulia Cusin and Ruth Durrer and Irina Dvorkin},
journal= {arXiv preprint arXiv:1912.11916},
year = {2020}
}