Strong-lensing of Gravitational Waves by Galaxy Clusters: Deep and rapid observations of galaxy clusters within the sky localisation of GW170814
Matteo Bianconi (University of Birmingham)
Tuesday 04/09/2018 @ 14:00, Sala Seminari IV piano Battiferro
Discovery of strongly-lensed gravitational wave sources will unveil binary compact objects at higher redshifts and lower intrinsic luminosities than is possible without lensing. Such systems will yield unprecedented constraints on the mass distribution in galaxy clusters, measurements of the polarization of GWs, tests of General Relativity, and constraints on the Hubble parameter. Excited by these prospects, and intrigued by the presence of so-called "heavy black holes" in the early detections by LIGO-Virgo, we commenced a search for strongly-lensed gravitational waves and possible electromagnetic counterparts in the latter stages of the second LIGO observing run. In particular, we present observations of two strong-lensing galaxy clusters located within the 90 per cent credible sky localization released following LIGO-Virgo's discovery of the binary black hole source GW170814. This is the first emission-line search for optical counterparts to gravitational wave sources, and the most sensitive continuum search to date - we reach an apparent magnitude limit before correction for lens magnification that is more than ?2 magnitudes fainter than previous searches.