Searching for A Generic Gravitational Wave Background via Bayesian Nonparametric Analysis with Pulsar Timing Arrays

Abstract

Gravitational wave background results from the superposition of gravitational waves generated from all sources across the Universe. Previous efforts on detecting such a background with pulsar timing arrays assume it is an isotropic Gaussian background with a power law spectrum. However, when the number of sources is limited, the background might be non-Gaussian or the spectrum might not be a power law. Correspondingly previous analysis may not work effectively. Here we use a method --- Bayesian Nonparametric Analysis --- to try to detect a generic gravitational wave background, which directly sets constraints on the feasible shapes of the pulsar timing signals induced by a gravitational wave background and allows more flexible forms of the background. Our Bayesian nonparametric analysis will infer if a gravitational wave background is present in the data, and also estimate the parameters that characterize the background. This method will be much more effective than the conventional one assuming the background spectrum follows a power law in general cases. While the context of our discussion focuses on pulsar timing arrays, the analysis itself is directly applicable to detect and characterize any signals that arise from the superposition of a large number of astrophysical events.

Accepted for publication in Physical Review D. arXiv admin note: text overlap with arXiv:1404.0663

References in corpus (8)

• The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) Project
• The stochastic gravitational-wave background from massive black hole binary systems: implications for observations with Pulsar Timing Arrays
• Upper bounds on the low-frequency stochastic gravitational wave background from pulsar timing observations: current limits and future prospects
• Assessing the Role of Spin Noise in the Precision Timing of Millisecond Pulsars
• On measuring the gravitational-wave background using Pulsar Timing Arrays
• Model-based asymptotically optimal dispersion measure correction for pulsar timing
• Bayesian estimation of non-Gaussianity in pulsar timing analysis
• Searching for Gravitational Wave Bursts via Bayesian Nonparametric Data Analysis with Pulsar Timing Arrays