The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background

Zaven Arzoumanian; Paul T Baker; Harsha Blumer; Bence Becsy; Adam Brazier; Paul R Brook; Sarah Burke-Spolaor; Shami Chatterjee; Siyuan Chen; James M Cordes; Neil J Cornish; Fronefield Crawford; H. Thankful Cromartie; Megan E DeCesar; Paul B Demorest; Timothy Dolch; Justin A Ellis; Elizabeth C Ferrara; William Fiore; Emmanuel Fonseca; Nathan Garver-Daniels; Peter A Gentile; Deborah C Good; Jeffrey S Hazboun; A. Miguel Holgado; Kristina Islo; Ross J Jennings; Megan L Jones; Andrew R Kaiser; David L Kaplan; Luke Zoltan Kelley; Joey Shapiro Key; Nima Laal; Michael T Lam; T. Joseph W Lazio; Duncan R Lorimer; Jing Luo; Ryan S Lynch; Dustin R Madison; Maura A McLaughlin; Chiara M. F Mingarelli; Cherry Ng; David J Nice; Timothy T Pennucci; Nihan S Pol; Scott M Ransom; Paul S Ray; Brent J Shapiro-Albert; Xavier Siemens; Joseph Simon; Renee Spiewak; Ingrid H Stairs; Daniel R Stinebring; Kevin Stovall; Jerry P Sun; Joseph K Swiggum; Stephen R Taylor; Jacob E Turner; Michele Vallisneri; Sarah J Vigeland; Caitlin A Witt

Journal article

The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background

Zaven Arzoumanian, Paul T Baker, Harsha Blumer, Bence Becsy, Adam Brazier, Paul R Brook, Sarah Burke-Spolaor, Shami Chatterjee, Siyuan Chen, James M Cordes, …

09/09/2020

Abstract

We search for an isotropic stochastic gravitational-wave background (GWB) in the $12.5$-year pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). Our analysis finds strong evidence of a stochastic process, modeled as a power-law, with common amplitude and spectral slope across pulsars. The Bayesian posterior of the amplitude for a $f^{-2/3}$ power-law spectrum, expressed as characteristic GW strain, has median $1.92 \times 10^{-15}$ and $5\%$--$95\%$ quantiles of $1.37$--$2.67 \times 10^{-15}$ at a reference frequency of $f_\mathrm{yr} = 1 ~\mathrm{yr}^{-1}$. The Bayes factor in favor of the common-spectrum process versus independent red-noise processes in each pulsar exceeds $10,000$. However, we find no statistically significant evidence that this process has quadrupolar spatial correlations, which we would consider necessary to claim a GWB detection consistent with General Relativity. We find that the process has neither monopolar nor dipolar correlations, which may arise from, for example, reference clock or solar-system ephemeris systematics, respectively. The amplitude posterior has significant support above previously reported upper limits; we explain this in terms of the Bayesian priors assumed for intrinsic pulsar red noise. We examine potential implications for the supermassive black hole binary population under the hypothesis that the signal is indeed astrophysical in nature.

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Title: The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
Creators - without role: Zaven Arzoumanian - for the NANOGrav Collaboration
Paul T Baker - for the NANOGrav Collaboration
Harsha Blumer - for the NANOGrav Collaboration
Bence Becsy - for the NANOGrav Collaboration
Adam Brazier - for the NANOGrav Collaboration
Paul R Brook - for the NANOGrav Collaboration
Sarah Burke-Spolaor - for the NANOGrav Collaboration
Shami Chatterjee - for the NANOGrav Collaboration
Siyuan Chen - for the NANOGrav Collaboration
James M Cordes - for the NANOGrav Collaboration
Neil J Cornish - for the NANOGrav Collaboration
Fronefield Crawford - for the NANOGrav Collaboration
H. Thankful Cromartie - for the NANOGrav Collaboration
Megan E DeCesar - for the NANOGrav Collaboration
Paul B Demorest - for the NANOGrav Collaboration
Timothy Dolch - for the NANOGrav Collaboration
Justin A Ellis - for the NANOGrav Collaboration
Elizabeth C Ferrara - for the NANOGrav Collaboration
William Fiore - for the NANOGrav Collaboration
Emmanuel Fonseca - for the NANOGrav Collaboration
Nathan Garver-Daniels - for the NANOGrav Collaboration
Peter A Gentile - for the NANOGrav Collaboration
Deborah C Good - for the NANOGrav Collaboration
Jeffrey S Hazboun - for the NANOGrav Collaboration
A. Miguel Holgado - for the NANOGrav Collaboration
Kristina Islo - for the NANOGrav Collaboration
Ross J Jennings - for the NANOGrav Collaboration
Megan L Jones - for the NANOGrav Collaboration
Andrew R Kaiser - for the NANOGrav Collaboration
David L Kaplan - for the NANOGrav Collaboration
Luke Zoltan Kelley - for the NANOGrav Collaboration
Joey Shapiro Key - for the NANOGrav Collaboration
Nima Laal - for the NANOGrav Collaboration
Michael T Lam - for the NANOGrav Collaboration
T. Joseph W Lazio - for the NANOGrav Collaboration
Duncan R Lorimer - for the NANOGrav Collaboration
Jing Luo - for the NANOGrav Collaboration
Ryan S Lynch - for the NANOGrav Collaboration
Dustin R Madison - for the NANOGrav Collaboration
Maura A McLaughlin - for the NANOGrav Collaboration
Chiara M. F Mingarelli - for the NANOGrav Collaboration
Cherry Ng - for the NANOGrav Collaboration
David J Nice - for the NANOGrav Collaboration
Timothy T Pennucci - for the NANOGrav Collaboration
Nihan S Pol - for the NANOGrav Collaboration
Scott M Ransom - for the NANOGrav Collaboration
Paul S Ray - for the NANOGrav Collaboration
Brent J Shapiro-Albert - for the NANOGrav Collaboration
Xavier Siemens - for the NANOGrav Collaboration
Joseph Simon - for the NANOGrav Collaboration
Renee Spiewak - for the NANOGrav Collaboration
Ingrid H Stairs - for the NANOGrav Collaboration
Daniel R Stinebring - for the NANOGrav Collaboration
Kevin Stovall - for the NANOGrav Collaboration
Jerry P Sun - for the NANOGrav Collaboration
Joseph K Swiggum - for the NANOGrav Collaboration
Stephen R Taylor - for the NANOGrav Collaboration
Jacob E Turner - for the NANOGrav Collaboration
Michele Vallisneri - for the NANOGrav Collaboration
Sarah J Vigeland - for the NANOGrav Collaboration
Caitlin A Witt - for the NANOGrav Collaboration
Identifiers: 991019295083907081
Academic Unit: Physics
Language: English
Resource Type: Journal article