Search for strongly lensed counterpart images of binary black hole mergers in the first two LIGO observing runs

Abstract

Strong gravitational lensing can produce multiple images of the same gravitational-wave signal, each arriving at different times and with different magnification. Previous work has explored if lensed pairs exist among the known high-significance events from the LIGO and Virgo Collaboration's GWTC-1 catalog and found no evidence of this. However, the possibility remains that weaker counterparts of these events are present in the data, unrecovered by previous searches. We conduct a targeted search specifically looking for subthreshold lensed images of known binary black hole (BBH) observations from GWTC-1. We recover candidates matching three of the additional events first reported by Venumadhav et al. [Phys. Rev. D 101, 083030 (2020)] but find no evidence for additional BBH events. We also find no evidence that any of the Venumadhav et al. observations are lensed counterparts. We demonstrate how this type of counterpart search can constrain hypotheses about the overall source and lens populations and we rule out at very high confidence the extreme hypothesis that all heavy BBH detections are in fact lensed systems at high redshift with intrinsic masses <15 M ⊙ .

Identifying type II strongly lensed gravitational-wave images in third-generation gravitational-wave detectors

“…There have been ongoing efforts to look for possible weaker (sub-threshold) strongly lensed counterparts of confirmed GW detections, assuming the latter being strongly lensed signals themselves [48,49]. One method is to simulate lensed injections of a super-threshold GW event, then use a generic template bank to search for these injections through an injection run, and produce a targeted template bank for searching possible lensed counterparts of the target event by retaining only templates that can find the injections.…”

Characteristic features of gravitational wave lensing as probe of lens mass model

“…One of the latest LIGO collaboration paper [6] focused exactly on finding any evidence of lensing in the registered signals. Other papers before [7][8][9][10][11] looked for lensing signature in GWs data, as well. None of them, though, gave positive results.…”

Microlensing of type II gravitational-wave macroimages

“…We have many examples of EM lensing observations (Ohanian 1974;Thorne 1982;Deguchi & Watson 1986;Wang et al 1996;Nakamura 1998;Takahashi & Nakamura 2003). Recently, searches for GW lensing using LIGO and Virgo data have also started (Hannuksela et al 2019;Li et al 2019a;McIsaac et al 2020;Pang et al 2020;Dai et al 2020;Liu et al 2020;Collaboration & Collaboration 2021), and many of the detection methodologies have been outlined in recent years (Cao et al 2014;Lai et al 2018;Christian et al 2018;Hannuksela et al 2019;Li et al 2019a;McIsaac et al 2020;Pang et al 2020;Hannuksela et al 2020;Dai et al 2020;Liu et al 2020;Wang et al 2021b;Lo & Magana Hernandez 2021;Janquart et al 2021a,b). If observed, lensed GWs could enable studies spanning the domains of fundamental physics, astrophysics, and cosmology Sereno et al (2011); Baker & Trodden (2017); Fan et al (2017); Liao et al (2017); Lai et al (2018); Liao (2019); Cao et al (2019); Li et al (2019b); Hou et al (2020); Mukherjee et al (2020a,b); Goyal et al (2020); Diego (2020); Hannuksela et al (2020);…”

“…The frequency evolution of the GW is still the same for these macroimages. Therefore, searches based on matched filtering and Bayesian analysis are used in the search of GW strong lensing (Haris et al 2018;Hannuksela et al 2019;Li et al 2019a;McIsaac et al 2020;Dai et al 2020;Liu et al 2020;Lo & Magana Hernandez 2021;Janquart et al 2021b,a).…”