Localization of GW190521 and reconstruction of the spin-2 gravitational-wave polarization modes

Abstract: We report on the new developments of the procedure L2D+PMR for sky localization\citep{KAGRA:2013rdx} using data from two gravitational-wave detectors and the reconstruction of gravitational-wave polarization modes\citep{Poisson2014}, which we have previously presented\citep{Moreschi25a}. In this case we apply our methods to the GW190521\citep{Abbott:2020tfl} event, which was recorded by three gravitational-wave observatories. We find the localization of the source close to one of the crossings of two delay rings, as expected. Thus, our results corroborate the consistency of the procedure. We compare our findings with those obtained by the LIGO/Virgo Collaborations, providing an independent assessment of gravitational-wave localization. We present the second direct measurement of spin-2 gravitational-wave polarization modes.