The NANOGrav 11-year Data Set: Pulsar-timing Constraints On The Stochastic Gravitational-wave Background

• Published in: arXiv.org 2018-06
• Main Authors: Arzoumanian, Z, Baker, P T, Brazier, A, Burke-Spolaor, S, Chamberlin, S J, Chatterjee, S, Christy, B, Cordes, J M, Cornish, N J, Crawford, F, Cromartie, H Thankful, Crowter, K, DeCesar, M, Demorest, P B, Dolch, T, Ellis, J A, Ferdman, R D, Ferrara, E, Folkner, W M, Fonseca, E, Garver-Daniels, N, Gentile, P A, Haas, R, Hazboun, J S, Huerta, E A, Islo, K, Jones, G, Jones, M L, Kaplan, D L, Kaspi, V M, Lam, M T, Lazio, T J W, Levin, L, Lommen, A N, Lorimer, D R, Luo, J, Lynch, R S, Madison, D R, McLaughlin, M A, McWilliams, S T, Mingarelli, C M F, C Ng, Nice, D J, Park, R S, Pennucci, T T, Pol, N S, Ransom, S M, Ray, P S, Rasskazov, A, Siemens, X, Simon, J, Spiewak, R, Stairs, I H, Stinebring, D R, Stovall, K, Swiggum, J, Taylor, S R, Vallisneri, M, Vigeland, S, Zhu, W W
• Format: Article
• Language: English
• Subjects: Binary stars; Computer simulation; Flux density; Gravitation; Gravitational waves; Pulsars; Solar system; Stellar mass; Strings; Uncertainty; Universe
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1801.02617

We search for an isotropic stochastic gravitational-wave background (GWB) in the newly released \(11\)-year dataset from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). While we find no significant evidence for a GWB, we place constraints on a GWB from a population of supermassive black-hole binaries, cosmic strings, and a primordial GWB. For the first time, we find that the GWB upper limits and detection statistics are sensitive to the Solar System ephemeris (SSE) model used, and that SSE errors can mimic a GWB signal. We developed an approach that bridges systematic SSE differences, producing the first PTA constraints that are robust against SSE uncertainties. We thus place a \(95\%\) upper limit on the GW strain amplitude of \(A_\mathrm{GWB}