Consistency of the Parkes Pulsar Timing Array Signal with a Nanohertz Gravitational-wave Background

Abstract

Pulsar timing array experiments have recently reported strong evidence for a common-spectrum stochastic process with a strain spectral index consistent with that expected of a nanohertz-frequency gravitational-wave background, but with negligible yet non-zero evidence for spatial correlations required for a definitive detection. However, it was pointed out by the Parkes Pulsar Timing Array (PPTA) collaboration that the same models used in recent analyses resulted in strong evidence for a common-spectrum process in simulations where none is present. In this work, we introduce a methodology to distinguish pulsar power spectra with the same amplitude from noise power spectra of similar but distinct amplitudes. The former is the signature of a spatially uncorrelated pulsar term of a nanohertz gravitational-wave background, whereas the latter could represent ensemble pulsar noise properties. We test the methodology on simulated data sets. We find that the reported common process in PPTA pulsars is indeed consistent with the spectral feature of a pulsar term. We recommend this methodology as one of the validity tests that the real astrophysical and cosmological backgrounds should pass, as well as for inferences about the spatially uncorrelated component of the background.

9 pages, 2 figures

References in corpus (18)

• The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
• Tempo2, a new pulsar timing package. II: The timing model and precision estimates
• The International Pulsar Timing Array second data release: Search for an isotropic Gravitational Wave Background
• On the evidence for a common-spectrum process in the search for the nanohertz gravitational-wave background with the Parkes Pulsar Timing Array
• Common-red-signal analysis with 24-yr high-precision timing of the European Pulsar Timing Array: Inferences in the stochastic gravitational-wave background search
• Assessing the Role of Spin Noise in the Precision Timing of Millisecond Pulsars
• On measuring the gravitational-wave background using Pulsar Timing Arrays
• Astrophysics Milestones For Pulsar Timing Array Gravitational Wave Detection
• Identifying and mitigating noise sources in precision pulsar timing data sets
• Massive black hole evolution models confronting the n-Hz amplitude of the stochastic gravitational wave background
• The Parkes pulsar timing array second data release: Timing analysis
• Noise analysis in the European Pulsar Timing Array data release 2 and its implications on the gravitational-wave background search
• Common-spectrum process versus cross-correlation for gravitational-wave searches using pulsar timing arrays
• A quasar-based supermassive black hole binary population model: implications for the gravitational-wave background
• When models fail: an introduction to posterior predictive checks and model misspecification in gravitational-wave astronomy
• Weighing The Evidence For A Gravitational-Wave Background In The First International Pulsar Timing Array Data Challenge
• Rapid parameter estimation of a two-component neutron star model with spin wandering using a Kalman filter
• A Parallelized Bayesian Approach To Accelerated Gravitational-Wave Background Characterization

Cited by in corpus (29)

• The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background
• Search for an isotropic gravitational-wave background with the Parkes Pulsar Timing Array
• Searching for the nano-Hertz stochastic gravitational wave background with the Chinese Pulsar Timing Array Data Release I
• The second data release from the European Pulsar Timing Array III. Search for gravitational wave signals
• The second data release from the European Pulsar Timing Array I. The dataset and timing analysis
• The Parkes Pulsar Timing Array Third Data Release
• Inflationary interpretation of the stochastic gravitational wave background signal detected by pulsar timing array experiments
• The gravitational-wave background null hypothesis: Characterizing noise in millisecond pulsar arrival times with the Parkes Pulsar Timing Array
• The second data release from the European Pulsar Timing Array II. Customised pulsar noise models for spatially correlated gravitational waves
• The MeerKAT Pulsar Timing Array: The first search for gravitational waves with the MeerKAT radio telescope
• The second data release from the European Pulsar Timing Array: VI. Challenging the ultralight dark matter paradigm
• Single field inflation in the light of Pulsar Timing Array Data: Quintessential interpretation of blue tilted tensor spectrum through Non-Bunch Davies initial condition
• The NANOGrav 15-year Gravitational-Wave Background Methods
• Accurate characterization of the stochastic gravitational-wave background with pulsar timing arrays by likelihood reweighting
• The NANOGrav 12.5-year Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
• Evaluating the prevalence of spurious correlations in pulsar timing array datasets
• Reading the tea leaves in the $M_{\mathrm{bh}}$-$M_{\ast ,\mathrm{sph}}$ and $M_{\mathrm{bh}}$-$R_{\mathrm{e},\mathrm{sph}}$ diagrams: dry and gaseous mergers with remnant angular momentum
• Status Report on Global Pulsar-Timing-Array Efforts to Detect Gravitational Waves
• The MeerKAT Pulsar Timing Array: Maps of the gravitational-wave sky with the 4.5 year data release
• Pulsar Timing Arrays require hierarchical models
• Posterior predictive checking for gravitational-wave detection with pulsar timing arrays: I. The optimal statistic
• Splitting the lentils: Clues to galaxy/black hole coevolution from the discovery of offset relations for non-dusty versus dusty (wet-merger-built) lenticular galaxies in the $M_{\mathrm{bh}}$-$M_{\ast ,\mathrm{spheroid}}$ diagram
• Ensemble noise properties of the European Pulsar Timing Array
• Seeing the gravitational wave universe
• Posterior predictive checking for gravitational-wave detection with pulsar timing arrays: II. Posterior predictive distributions and pseudo Bayes factors
• Reading signatures of supermassive binary black holes in pulsar timing array observations
• Rapid Construction of Joint Pulsar Timing Array Datasets: The Lite Method
• Theoretical Radio Signals from Radio-Band Gravitational Waves Converted from the Neutron Star Magnetic Field
• Pulsar Timing Response to Gravitational Waves with Spherical Wavefronts from a Massive Compact Source in the Quadrupole Approximation