REVIEW 18 cited by
Beyond diagonal approximations: improved covariance modeling for pulsar timing array data analysis
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
Beyond diagonal approximations: improved covariance modeling for pulsar timing array data analysis
read the original abstract
Pulsar Timing Array (PTA) searches for nHz gravitational-wave backgrounds (GWBs) typically model time-correlated noise by assuming a diagonal covariance in Fourier space, neglecting inter-frequency correlations introduced by the finite observation window. We show that this diagonal approximation can lead to biased estimates of spectral parameters, especially for the common red process that represents the GWB. To address these limitations, we present a method that (i) computes the time-domain autocorrelation on a coarse grid using a fast Fourier transform (FFT), (ii) interpolates it accurately to the unevenly sampled observation times, and (iii) incorporates it into a low-rank likelihood via the Sherman--Morrison--Woodbury identity. Using both analytic covariance comparisons and end-to-end simulations inspired by the NANOGrav 15-year dataset, we demonstrate that our method captures frequency correlations faithfully, avoids Gibbs ringing, and recovers unbiased spectral parameters with modest computational cost. As PTA datasets increase in sensitivity and complexity, our approach offers a practical and scalable path to fully accurate covariance modeling for current and future analyses.
Forward citations
Cited by 18 Pith papers
-
A new framework for lightning-fast gravitational wave analysis of pulsar timing data
A standardizing coordinate transform turns PTA Fourier coefficients into near-standard normals so HMC/NUTS on GPU recovers NANOGrav-scale posteriors in ~15 minutes.
-
Modeling non-stationary noise: applications in gravitational wave astronomy
A positive dynamic spectrum S(f,t) generalizes the stationary power spectrum by defining Gramian closed-form noise covariances in Fourier and Wilson-Daubechies wavelet bases for gravitational wave data.
-
Comparing gravitational wave background predictions from cosmological simulations to pulsar timing observations
FABLE simulation predictions for the nanohertz gravitational wave background are statistically consistent with NANOGrav 15-year data at 1–2.5σ tension, with physically motivated population modifications further improv...
-
Are PTA measurements sensitive to gravitational wave non-Gaussianities?
PTA statistical tests cannot distinguish Gaussian and non-Gaussian GWB amplitude distributions in a model-agnostic way after decorrelation.
-
Are PTA measurements sensitive to gravitational wave non-Gaussianities?
PTA statistical tests lose sensitivity to non-Gaussian GW features after decorrelation and cannot distinguish them model-agnostically.
-
A comprehensive framework for phase-coherent mapping of the gravitational-wave sky with pulsar timing arrays
A new phase-coherent mapping framework for pulsar timing arrays that preserves the complete complex polarization state of the gravitational-wave sky in compact maps usable for multiple analyses.
-
Timing Gamma-ray Pulsars using Gibbs Sampling
A Gibbs sampling technique marginalizes over photon-to-Gaussian assignments to fit timing and noise models to discrete gamma-ray arrival times while accounting for pulse-profile uncertainty.
-
Stochastic gravitational-wave background search using data from five pulsar timing arrays
Combined five-PTA dataset yields posterior on SGWB power-law amplitude and index consistent with nonzero signal but below 5-sigma significance, with reconstructed angular correlations matching the Hellings-Downs prediction.
-
Data span and frequency coverage requirements for robust detection and inference in PTAs: A case study with EPTA DR2
Sparse early frequency coverage and noise fluctuations explain why EPTA DR2's shorter subset reports higher GWB significance than the full 25-year dataset.
-
Finite Populations & Finite Time: The Non-Gaussianity of a Gravitational Wave Background
Finite source number and finite observation time make PTA gravitational-wave-background Fourier coefficients non-Gaussian, with an analytically computed excess kurtosis and a Cauchy-distributed argument probe.
-
Finite Populations & Finite Time: The Non-Gaussianity of a Gravitational Wave Background
Finite populations of inspiralling supermassive black hole binaries plus finite observation windows introduce non-Gaussian statistics in the pulsar timing array signal that are absent from the Gaussian approximation u...
-
Finding Supermassive Black Hole Binary Mergers in Pulsar Timing Array Data
A complete SMBHB waveform model enables unified PTA searches for mergers and memory signals, with parameter recovery shown on simulated data for 10^8-10^10 solar mass systems.
-
The NANOGrav 15 yr Data Set: Customized Chromatic Noise Models
Customized chromatic noise models for 67 pulsars detect non-dispersive delays in 21 cases, alter achromatic noise inferences in 19, and enable solar wind density estimates over 1.5 cycles.
-
Stochastic problems in pulsar timing
Analytical solutions to Langevin equations for red noise and GWB in pulsars show that an Ornstein-Uhlenbeck spin frequency model is inconsistent with stationary signals, while an overdamped oscillator model and a two-...
-
Expectations for the first supermassive black-hole binary resolved by PTAs II: Milestones for binary characterization
Simulations of continuous-wave searches show that PTA data first constrain GW frequency and strain amplitude together, then sky location, with chirp mass and inclination following later for evolving sources, with prec...
-
Expectations for the first supermassive black-hole binary resolved by PTAs I: Model efficacy
Simulations of PTA data show that a full gravitational-wave signal template achieves the highest Bayes factors and most robust parameter estimation for individual supermassive black hole binaries compared to an Earth-...
-
Directional Anisotropic Sensitivity Curves for Pulsar Timing Arrays
PTA gravitational-wave sensitivity is mapped direction-by-direction, with radiometer and full-Fisher estimators bracketing the usual isotropic curve.
-
The NANOGrav 15 yr Data Set: Impacts of Customized Chromatic Noise Models on Gravitational Wave Analyses
Customized chromatic noise models applied to NANOGrav 15 yr data raise the Bayes factor for Hellings-Downs GWB correlations by a factor of ~8, lower the amplitude to 2.1e-15, and increase the spectral index to 3.5.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.