On detection of the stochastic gravitational-wave background using the Parkes pulsar timing array

TL;DR

This paper searches for a stochastic gravitational-wave background using 12 years of pulsar timing data from Parkes and Arecibo, discussing unique signal processing challenges and finding no significant detection with 76% confidence.

Contribution

It introduces a frequency-domain correlation technique tailored for pulsar timing data and addresses specific spectral leakage issues not previously explored.

Findings

Data is consistent with no gravitational-wave background detection.

Detection is dominated by a few pulsars due to data inhomogeneity.

Discusses future detection challenges and strategies.

Abstract

We search for the signature of an isotropic stochastic gravitational-wave background in pulsar timing observations using a frequency-domain correlation technique. These observations, which span roughly 12 yr, were obtained with the 64-m Parkes radio telescope augmented by public domain observations from the Arecibo Observatory. A wide range of signal processing issues unique to pulsar timing and not previously presented in the literature are discussed. These include the effects of quadratic removal, irregular sampling, and variable errors which exacerbate the spectral leakage inherent in estimating the steep red spectrum of the gravitational-wave background. These observations are found to be consistent with the null hypothesis, that no gravitational-wave background is present, with 76 percent confidence. We show that the detection statistic is dominated by the contributions of only a few pulsars because of the inhomogeneity of this data set. The issues of detecting the signature of a gravitational-wave background with future observations are discussed.