SMuK 2021 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 4: Gravitational waves

GR 4.5: Talk

Tuesday, August 31, 2021, 18:00–18:15, H6

Search for lensing signatures in the gravitational-wave observations from the first half of LIGO-Virgo's third observing run — •David Keitel for the LIGO-Virgo collaboration — Departament de Física, Edifici Mateu Orfila, Universitat de les Illes Balears, Carretera de Valldemossa, km 7,5, 07122 Palma de Mallorca, Illes Balears, Spain

The Advanced LIGO and Advanced Virgo detectors are now observing large numbers of gravitational-wave signals from compact binary coalescences, with 50 entries in the latest catalogue GWTC-2. With this rapidly growing event rate, our chances become better to detect rare astrophysical effects on these novel cosmic messengers. One such rare effect with a long and productive history in electromagnetic astronomy and great potential for the future of GW astrophysics is gravitational lensing. This presentation covers the first LIGO-Virgo collaboration search for lensing signatures in data from the O3a observing run. We study: 1) the expected rate of lensing at current detector sensitivity and the implications of a non-observation of strong lensing or a stochastic gravitational-wave background on the merger-rate density at high redshift; 2) how the interpretation of individual high-mass events would change if they were found to be lensed; 3) the possibility of multiple images due to strong lensing by galaxies or galaxy clusters; and 4) possible wave-optics effects due to point-mass microlenses. Overall, we find no compelling evidence for lensing in the observed gravitational-wave signals from any of these analyses.