By: Valeria Sequino, Gilles Theureau, Ben Stappers, Lucas Guillemot, Cristiano Palomba, Unité Scientifique, Ornella J Piccinni, Ismael Cognard, Michael J Keith, Jim Palfreyman, Bradley W Meyers, Chris Flynn, Lucia Trozzo, Paola Leaci, James W Mckee, Andrew L
The 5n-vector ensemble method is a multiple test for the targeted search of continuous gravitational waves from an ensemble of known pulsars. This method can improve the detection probability combining the results from individually undetectable pulsars if few signals are near the detection threshold. In this paper, we apply the 5n-vector ensemble method to the O3 data set from the LIGO and Virgo detectors considering an ensemble of 201 known pulsars. We find no evidence for a signal from the ensemble and set a 95% credible upper limit on the mean ellipticity assuming a common exponential distribution for the pulsars' ellipticities. Using two independent hierarchical Bayesian procedures, we find upper limits of
