REVIEW 6 cited by
Forecasting pulsar timing array sensitivity to anisotropy in the stochastic gravitational wave background
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
abstract
Statistical anisotropy in the nanohertz-frequency gravitational-wave background (GWB) is expected to be detected by pulsar timing arrays (PTAs) in the near future. By developing a frequentist statistical framework that intrinsically restricts the GWB power to be positive, we establish scaling relations for multipole-dependent anisotropy decision thresholds that are a function of the noise properties, timing baselines, and cadences of the pulsars in a PTA. We verify that $(i)$ a larger number of pulsars, and $(ii)$ factors that lead to lower uncertainty on the cross-correlation measurements between pulsars, lead to a higher overall GWB signal-to-noise ratio, and lower anisotropy decision thresholds with which to reject the null hypothesis of isotropy. Using conservative simulations of realistic NANOGrav datasets, we predict that an anisotropic GWB with angular power $C_{l=1} > 0.3\,C_{l=0}$ may be sufficient to produce tension with isotropy at the $p = 3\times10^{-3}$ ($\sim3\sigma$) level in near-future NANOGrav data with a $20$~yr baseline. We present ready-to-use scaling relationships that can map these thresholds to any number of pulsars, configuration of pulsar noise properties, and sky coverage. We discuss how PTAs can improve the detection prospects for anisotropy, as well as how our methods can be adapted for more versatile searches.
Forward citations
Cited by 6 Pith papers
-
Bias from small-scale leakage in Pulsar Timing Array maps
Unmodeled small-scale gravitational-wave power systematically inflates reconstructed large-scale angular power spectra in pulsar timing array anisotropy searches.
-
Mapping the Gravitational-wave Background Across the Spectrum with a Next-Generation Anisotropic Per-frequency Optimal Statistic
A new pulsar-timing-array pipeline maps the gravitational-wave sky per frequency, folds cosmic variance into significance estimates, and detects a simulated loud source at p=0.01 versus 0.2 broadband.
-
Mitigating cosmic variance in the Hellings-Downs curve: a Cosmic Microwave Background analogy
An optimal multipole-space frequency weighting shows that PTA cosmic variance can be reduced with longer observations and better cadence, and the CMB would show a Hellings-Downs curve only if n_T>4.
-
Estimating the gravitational wave background anisotropy: a Bayesian approach boosted by cross-correlation angular power spectrum
A new likelihood function estimates GWB anisotropy angular power spectra directly from detector data, and cross-correlation with the CMB can make the quadrupole measurable with four years of LISA data.
-
Cosmic Variance in Anisotropy Searches at Pulsar Timing Arrays
Cosmic variance does not create false anisotropy detections in pulsar timing array searches when the correct likelihood is used, and the maximum resolvable multipole scales as the number of pulsars rather than its squ...
-
Population Synthesis of Gravitational Wave Sources
A review of population synthesis: the codes, the environments, and the predicted rates and features of gravitational wave sources, with an emphasis on breaking degeneracies.
Discussion (0). Continue with ORCID to comment.