False positives for gravitational lensing: the gravitational-wave perspective
D. Keitel
Abstract
For the first detection of a novel astrophysical phenomenon, scientific standards are particularly high. Especially in a multi-messenger context, there are also opportunity costs to follow-up observations on any detection claims. So in searching for the still-elusive lensed gravitational waves (GWs), care needs to be taken in controlling false positives. In particular, many methods for identifying strong lensing rely on some form of parameter similarity or waveform consistency, which under rapidly growing catalogue sizes can expose them to false positives from coincident but unlensed events if proper care is not taken. Searches for waveform deformations in all lensing regimes are subject to degeneracies; we need to mitigate between lensing, intrinsic parameters, insufficiently modelled effects such as orbital eccentricity, or even deviations from general relativity. Robust lensing studies also require understanding and mitigation of glitches and non-stationarities in the detector data. This article reviews sources of possible false positives (and their flip side: false negatives) in GW lensing searches and the main approaches the community is pursuing to mitigate them.This article is part of the Theo Murphy meeting issue 'Multi-messenger gravitational lensing (Part 2)'.