Preprint

PUBDB-2023-05304

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background

Agazie, G. ; Anumarlapudi, A. ; Archibald, A. M. ; Arzoumanian, Z. ; Baker, P. T. ; Bécsy, B. ; Blecha, L. ; Brazier, A. ; Brook, P. R. ; Burke-Spolaor, S. ; Burnette, R. ; Case, R. ; Charisi, M. ; Chatterjee, S. ; Chatziioannou, K. ; Cheeseboro, B. D. ; Chen, S. ; Cohen, T. ; Cordes, J. M. ; Cornish, N. J. ; Crawford, F. ; Cromartie, H. T. ; Crowter, K. ; Cutler, C. J. ; DeCesar, M. E. ; DeGan, D. ; Demorest, P. B. ; Deng, H. ; Dolch, T. ; Drachler, B. ; Ellis, J. A. ; Ferrara, E. C. ; Fiore, W. ; Fonseca, E. ; Freedman, G. E. ; Garver-Daniels, N. ; Gentile, P. A. ; Gersbach, K. A. ; Glaser, J. ; Good, D. C. ; Gültekin, K. ; Hazboun, J. S. ; Hourihane, S. ; Islo, K. ; Jennings, R. J. ; Johnson, A. D. ; Jones, M. L. ; Kaiser, A. R. ; Kaplan, D. L. ; Kelley, L. Z. ; Kerr, M. ; Key, J. S. ; Klein, T. C. ; Laal, N. ; Lam, M. T. ; Lamb, W. G. ; W. Lazio, T. J. ; Lewandowska, N. ; Littenberg, T. B. ; Liu, T. ; Lommen, A. ; Lorimer, D. R. ; Luo, J. ; Lynch, R. S. ; Ma, C.-P. ; Madison, D. R. ; Mattson, M. A. ; McEwen, A. ; McKee, J. W. ; McLaughlin, M. A. ; McMann, N. ; Meyers, B. W. ; Meyers, P. M. ; Mingarelli, C. M. F. ; Mitridate, A.DESY* ; Natarajan, P. ; Ng, C. ; Nice, D. J. ; Ocker, S. K. ; Olum, K. D. ; Pennucci, T. T. ; Perera, B. B. P. ; Petrov, P. ; Pol, N. S. ; Radovan, H. A. ; Ransom, S. M. ; Ray, P. S. ; Romano, J. D. ; Sardesai, S. C. ; Schmiedekamp, A. ; Schmiedekamp, C. ; Schmitz, K. ; Schult, L. ; Shapiro-Albert, B. J. ; Siemens, X. ; Simon, J. ; Siwek, M. S. ; Stairs, I. H. ; Stinebring, D. R. ; Stovall, K. ; Sun, J. P. ; Susobhanan, A. ; Swiggum, J. K. ; Taylor, J. ; Taylor, S. R. ; Turner, J. E. ; Unal, C. ; Vallisneri, M. ; van Haasteren, R. ; Vigeland, S. J. (Corresponding author) ; Wahl, H. M. ; Wang, Q. ; Witt, C. A. ; Young, O.

2023
Institute of Physics Publ. London

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Please use a persistent id in citations: doi:10.3204/PUBDB-2023-05304

Report No.: arXiv:2306.16213

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$^{−3}$ (≈3σ) 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$^{−4}$ (≈3.5σ–4σ). Assuming a fiducial f$^{−2/3}$ characteristic strain spectrum, as appropriate for an ensemble of binary supermassive black hole inspirals, the strain amplitude is (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.

Note: 30 pages, 18 figures. Published in Astrophysical Journal Letters as part of Focus on NANOGrav's 15-year Data Set and the Gravitational Wave Background. For questions or comments, please email comments@nanograv.org

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Contributing Institute(s):

1. Theorie-Gruppe (T)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)
2. DFG project G:(GEPRIS)390833306 - EXC 2121: Quantum Universe (390833306) (390833306)
3. GRK 2149 - GRK 2149: Starke und schwache Wechselwirkung - von Hadronen zu Dunkler Materie (269952272) (269952272)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2023

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Database coverage:
; ; Published

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Journal Article Afzal, A. ; Agazie, G. ; Anumarlapudi, A. ; et al
The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background
The astrophysical journal / Part 2 951(1), L8 (2023) [10.3847/2041-8213/acdac6]2023     Files  Fulltext by arXiv.org BibTeX | EndNote: XML, Text | RIS

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