The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background

2023/06/28 by Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +133 · 5 voices · 154 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research

paper · pdf · doi:10.3847/2041-8213/acdac6

openalex publication_date 2023/06/29 · openalex created_date 2023/06/29 · openalex updated_date 2026/07/29

Abstract

Abstract We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves. The correlations follow the Hellings–Downs pattern expected for a stochastic gravitational-wave background. The presence of such a gravitational-wave background with a power-law spectrum is favored over a model with only independent pulsar noises with a Bayes factor in excess of 10 14 , and this same model is favored over an uncorrelated common power-law spectrum model with Bayes factors of 200–1000, depending on spectral modeling choices. We have built a statistical background distribution for the latter Bayes factors using a method that removes interpulsar correlations from our data set, finding p = 10 −3 (≈3 σ ) for the observed Bayes factors in the null no-correlation scenario. A frequentist test statistic built directly as a weighted sum of interpulsar correlations yields p = 5 × 10 −5 to 1.9 × 10 −4 (≈3.5 σ –4 σ ). Assuming a fiducial f −2/3 characteristic strain spectrum, as appropriate for an ensemble of binary supermassive black hole inspirals, the strain amplitude is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>2.4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.7</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>15</mml:mn> </mml:mrow> </mml:msup> </mml:math> (median + 90% credible interval) at a reference frequency of 1 yr −1 . The inferred gravitational-wave background amplitude and spectrum are consistent with astrophysical expectations for a signal from a population of supermassive black hole binaries, although more exotic cosmological and astrophysical sources cannot be excluded. The observation of Hellings–Downs correlations points to the gravitational-wave origin of this signal.

Citations

• The Weighted Likelihood Ratio, Linear Hypotheses on Normal Location Parameters
• A Monte Carlo method for high dimensional integration
• Observation of Gravitational Waves from a Binary Black Hole Merger
• The JPL Planetary and Lunar Ephemerides DE440 and DE441

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Discussions

• 🧪 Some lovely plots for the history books: the Hellings-Downs curve, predicted in 1983, and finally observed by NANOGrav! Their detection paper is up now: arxiv.org/abs/2306.16213 [bsky, 14 points, 0 comments]
• Here's the main NANOGrav paper on arxiv https://arxiv.org/abs/2306.16213 [bsky, 6 points, 0 comments]
• If you don’t have an inflaton, you can still source a primordial stochastic GW background via causal stress energy in the early plasma or maybe via nonlinear mode coupling. These are the non inflation [stackexchange, 6 points]
• The NANOGrav collaboration’s paper is up on the Arxiv https://arxiv.org/abs/2306.16213. We all get to learn about the gravitational wave background tomorrow, and the mind-blowing science of pulsar tim [bsky, 3 points, 0 comments]
• Lovely coordination of the pulsar timing papers on the arXiv today: 1 @NANOGrav headline https://arxiv.org/abs/2306.16213 2 @EPTAGW headline https://arxiv.org/abs/2306.16214 3 @CSIRO_ATNF headline htt [bsky, 0 points, 1 comments]

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