Controlling outlier contamination in multimessenger time-domain searches for supermasssive binary black holes

Abstract

ABSTRACT Time-domain data sets of many varieties can be prone to statistical outliers that result from instrumental or astrophysical anomalies. These can impair searches for signals within the time series and lead to biased parameter estimation. Versatile outlier mitigation methods tuned toward multimessenger time-domain searches for supermassive binary black holes have yet to be fully explored. In an effort to perform robust outlier isolation with low computational costs, we propose a Gibbs sampling scheme. This provides structural simplicity to outlier modelling and isolation, as it requires minimal modifications to adapt to time-domain modelling scenarios with pulsar-timing array or photometric data. We robustly diagnose outliers present in simulated pulsar-timing data sets, and then further apply our methods to pulsar J1909−3744 from the NANOGrav 9-year Data set. We also explore the periodic binary-AGN candidate PG1302−102 using data sets from the Catalina Real-time Transient Survey, All-Sky Automated Survey for Supernovae, and the Lincoln Near-Earth Asteroid Research. We present our findings and outline future work that could improve outlier modelling and isolation for multimessenger time-domain searches.