The NANOGrav 12.5 yr Data Set: Search for an Isotropic Stochastic Gravitational-wave Background
Year: 2020
Type: article
Abstract: We search for an isotropic stochastic gravitational-wave background (GWB) in the 12.5 yr pulsar-timing data set collected by the North American Nanohertz Observatory for Gravitational Waves. Our analysis finds strong evidence of a stochastic process, modeled as a power law, with common amplitude and spectral slope across pulsars. Under our fiducial model, the Bayesian posterior of the amplitude for an f −2/3 power-law spectrum, expressed as the characteristic GW strain, has median 1.92 × 10 −15 and 5%–95% quantiles of 1.37–2.67 × 10 −15 at a reference frequency of f yr = 1 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.
Authors: Zaven Arzoumanian, Paul T. Baker, Harsha Blumer, Bence Bécsy, 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, Renée 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
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, National Aeronautics and Space Administration, California Institute of Technology, Canadian Institute for Advanced Research, University of Central Florida, National Radio Astronomy Observatory, Associated Universities, Flatiron Health, Magyar Tudományos Akadémia, Eötvös Loránd Tudományegyetem, Jet Propulsion Laboratory, Natural Sciences and Engineering Research Council of Canada, Office of Naval Research, Office of Experimental Program to Stimulate Competitive Research
Awards: NANOGrav Physics Frontier Center, G1972360803, Enabling multi-messenger science with pulsar timing arrays, G4961910479, RII Track-1: Gravitational Wave Astronomy and the Appalachian Freshwater Initiative, Management and Operations of the Arecibo Observatory, G5541682171, MRI: Development of high-performance computing facility for gravitational-wave data analysis, Bionanotechnology for Public Security and Environmental Safety
OpenAlex ID: W3084270918