Strong lensing of high-energy neutrinos

Abstract

We consider the effects of strong gravitational lensing by galaxy-scale deflectors on the observations of high-energy ($\mathrm{E}\ensuremath{\gg}\mathrm{GeV}$) neutrinos (HENs). For HENs at cosmological distances, the optical depth for multiple imaging is $\ensuremath{\sim}{10}^{\ensuremath{-}3}$, implying that while we do not expect any multiply imaged HENs with present samples, next-generation experiments should be able to detect the first such event. We then present the distribution of expected time delays to aid in the identification of such events, in combination with directional and energy information. In order to assist in the evaluation of HEN production mechanisms, we illustrate how lensing affects the observed number counts for a variety of intrinsic luminosity functions of the source population. Finally, we see that the lensing effects on the cosmic neutrino background flux calculation would be negligible by taking kiloparsec-scale jets as an example.