The "Dropout Method”: A Bayesian technique for identifying spurious signals in pulsar timing arrays

Pulsar timing arrays (PTAs) detect gravitational waves (GWs) by looking for correlations in the pulse times of arrival of an array of millisecond pulsars (MSPs). A gravitational wave will affect many MSPs, whereas most noise sources should be confined to the residuals of a single pulsar. However, we have found that unmodeled signals in a single pulsar can be confused for a GW. I will present the "dropout method," which can be used to identify these spurious signals by determining how much each pulsar contributes to the signal, and discuss how it has been used in the analysis of the NANOGrav 11-year data set for GWs from individual supermassive black hole binaries.