The NANOGrav 15 yr Data Set: Search for Gravitational-wave Memory

Agazie, Gabriella; Anumarlapudi, Akash; Archibald, Anne M.; Arzoumanian, Zaven; Baier, Jeremy G.; Baker, Paul T.; Bécsy, Bence; Blecha, Laura; Brazier, Adam; Brook, Paul R.; Burke-Spolaor, Sarah; Burnette, Rand; Casey-Clyde, J. Andrew; Charisi, Maria; Chatterjee, Shami; Cohen, Tyler; Cordes, James M.; Cornish, Neil J.; Crawford, Fronefield; Cromartie, H. Thankful; Crowter, Kathryn; DeCesar, Megan E.; Demorest, Paul B.; Deng, Heling; Dey, Lankeswar; Dolch, Timothy; Ferrara, Elizabeth C.; Fiore, William; Fonseca, Emmanuel; Freedman, Gabriel E.; Gardiner, Emiko C.; Garver-Daniels, Nate; Gentile, Peter A.; Gersbach, Kyle A.; Glaser, Joseph; Good, Deborah C.; Gültekin, Kayhan; Hazboun, Jeffrey S.; Jennings, Ross J.; Johnson, Aaron D.; Jones, Megan L.; Kaplan, David L.; Kelley, Luke Zoltan; Kerr, Matthew; Key, Joey S.; Laal, Nima; Lam, Michael T.; Lamb, William G.; Larsen, Bjorn; Lazio, T. Joseph W.; Lewandowska, Natalia; Liu, Tingting; Lorimer, Duncan R.; Luo, Jing; Lynch, Ryan S.; Ma, Chung-Pei; Madison, Dustin R.; McEwen, Alexander; McKee, James W.; McLaughlin, Maura A.; McMann, Natasha; Meyers, Bradley W.; Meyers, Patrick M.; Mingarelli, Chiara M. F.; Mitridate, Andrea; Natarajan, Priyamvada; Ng, Cherry; Nice, David J.; Ocker, Stella Koch; Olum, Ken D.; Pennucci, Timothy T.; Perera, Benetge B. P.; Petrov, Polina; Pol, Nihan S.; Radovan, Henri A.; Ransom, Scott M.; Ray, Paul S.; Runnoe, Jessie C.; Saffer, Alexander; Sardesai, Shashwat C.; Schmiedekamp, Ann; Schmiedekamp, Carl; Schmitz, Kai; Shapiro-Albert, Brent J.; Siemens, Xavier; Simon, Joseph; Siwek, Magdalena S.; Fiscella, Sophia V. Sosa; Stairs, Ingrid H.; Stinebring, Daniel R.; Stovall, Kevin; Sun, Jerry P.; Susobhanan, Abhimanyu; Swiggum, Joseph K.; Taylor, Jacob; Taylor, Stephen R.; Turner, Jacob E.; Unal, Caner; Vallisneri, Michele; van Haasteren, Rutger; Vigeland, Sarah J.; Wahl, Haley M.; Witt, Caitlin A.; Wright, David; Young, Olivia

doi:10.3847/1538-4357/add874

Published June 23, 2025 | Version Published

Journal Article Open

The NANOGrav 15 yr Data Set: Search for Gravitational-wave Memory

1. University of Wisconsin–Milwaukee
2. Newcastle University
3. Goddard Space Flight Center
4. Oregon State University
5. Widener University
6. University of Florida
7. Cornell University
8. University of Birmingham
9. West Virginia University
10. United States Naval Research Laboratory
11. University of Connecticut
12. Vanderbilt University
13. New Mexico Institute of Mining and Technology
14. Montana State University
15. Franklin & Marshall College
16. National Academy of Sciences
17. Sloan Fellow.
18. University of British Columbia
19. George Mason University
20. National Radio Astronomy Observatory
21. Hillsdale College
22. Eureka Scientific
23. University of Maryland, College Park
24. University of California, Berkeley
25. Department of Physics and Astronomy, University of Montan, a, 32 Campus Drive, Missoula, MT 59812, USA
26. University of Michigan–Ann Arbor
27. NANOGrav Physics Frontiers Center Postdoctoral Fellow.
28. California Institute of Technology
29. University of Washington
30. Search for Extraterrestrial Intelligence
31. Rochester Institute of Technology
32. Yale University
33. Jet Propulsion Lab
34. State University of New York at Oswego
35. University of Toronto
36. Deceased.
37. Green Bank Observatory, P.O. Box 2, Green Bank, WV 24944, USA
38. University of the Pacific
39. Union College
40. International Centre for Radio Astronomy Research
41. Deutsches Elektronen-Synchrotron DESY
42. Harvard University
43. Lafayette College
44. Carnegie Observatories
45. Tufts University
46. Eötvös Loránd University
47. Arecibo Observatory
48. Texas Tech University
49. University of Puerto Rico System
50. Pennsylvania State University
51. University of Münster
52. Giant Army, 915A 17th Ave, Seattle, WA 98122, USA
53. University of Colorado Boulder
54. NSF Astronomy and Astrophysics Postdoctoral Fellow.
55. Harvard-Smithsonian Center for Astrophysics
56. Oberlin College
57. Max Planck Institute for Gravitational Physics
58. Middle East Technical University
59. Ben-Gurion University of the Negev
60. Feza Gürsey Institute
61. Northwestern University
62. Adler Planetarium

We present the results of a search for nonlinear gravitational-wave (GW) memory in the NANOGrav 15 yr data set. We find no significant evidence for memory signals in the data set, with a maximum Bayes factor of 3.1 in favor of a model including memory. We therefore place upper limits on the strain of potential GW memory events as a function of sky location and observing epoch. We find upper limits that are not always more constraining than previous NANOGrav results. We show that it is likely due to the increase in common red noise between the 12.5 and 15 yr NANOGrav data sets.

Copyright and License

© 2025. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

The work contained herein has been carried out by the NANOGrav collaboration, which receives support from the National Science Foundation (NSF) Physics Frontier Center award Nos. 1430284 and 2020265, the Gordon and Betty Moore Foundation, NSF AccelNet award No. 2114721, an NSERC Discovery Grant, and CIFAR. The Arecibo Observatory is a facility of the NSF operated under cooperative agreement (AST-1744119) by the University of Central Florida (UCF) in alliance with Universidad Ana G. Méndez (UAGM) and Yang Enterprises (YEI), Inc. The Green Bank Observatory is a facility of the NSF operated under cooperative agreement by Associated Universities, Inc. L.B. acknowledges support from the National Science Foundation under award AST-1909933 and from the Research Corporation for Science Advancement under Cottrell Scholar Award No. 27553. P.R.B. is supported by the Science and Technology Facilities Council, grant No. ST/W000946/1. S.B. gratefully acknowledges the support of a Sloan Fellowship, and the support of NSF under award #1815664. The work of R.B., N.La., X.S., J.P.S., J.T., and D.W. is partly supported by the George and Hannah Bolinger Memorial Fund in the College of Science at Oregon State University. M.C., P.P., and S.R.T. acknowledge support from NSF AST-2007993. M.C. was supported by the Vanderbilt Initiative in Data Intensive Astrophysics (VIDA) Fellowship. Support for this work was provided by the NSF through the Grote Reber Fellowship Program administered by Associated Universities, Inc./National Radio Astronomy Observatory. Pulsar research at UBC is supported by an NSERC Discovery Grant and by CIFAR. K.C. is supported by a UBC Four Year Fellowship (6456). M.E.D. acknowledges support from the Naval Research Laboratory by NASA under contract S-15633Y. T.D. and M.T.L. were supported by an NSF Astronomy and Astrophysics Grant (AAG) award No. 2009468 during this work. E.C.F. is supported by NASA under award No. 80GSFC24M0006. G.E.F., S.C.S., and S.J.V. are supported by NSF award PHY-2011772. K.A.G. and S.R.T. acknowledge support from an NSF CAREER award #2146016. A.D.J. and M.V. acknowledge support from the Caltech and Jet Propulsion Laboratory President’s and Director’s Research and Development Fund. A.D.J. acknowledges support from the Sloan Foundation. N.La. acknowledges the support from Larry W. Martin and Joyce B. O’Neill Endowed Fellowship in the College of Science at Oregon State University. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). D.R.L. and M.A.M. are supported by NSF #1458952. M.A.M. is supported by NSF #2009425. C.M.F.M. was supported in part by the National Science Foundation under grants No. NSF PHY-1748958 and AST-2106552. A.Mi. is supported by the Deutsche Forschungsgemeinschaft under Germany’s Excellence Strategy - EXC 2121 Quantum Universe - 390833306. The Dunlap Institute is funded by an endowment established by the David Dunlap family and the University of Toronto. P.N. acknowledges support from the BHI, funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation. K.D.O. was supported in part by NSF grant No. 2207267. T.T.P. acknowledges support from the Extragalactic Astrophysics Research Group at Eötvös Loránd University, funded by the Eötvös Loránd Research Network (ELKH), which was used during the development of this research. H.A.R. is supported by NSF Partnerships for Research and Education in Physics (PREP) award No. 2216793. S.M.R. and I.H.S. are CIFAR Fellows. Portions of this work performed at NRL were supported by ONR 6.1 basic research funding. J.D.R. also acknowledges support from start-up funds from Texas Tech University. J.S. is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-2202388, and acknowledges previous support by the NSF under award 1847938. C.U. acknowledges support from BGU (Kreitman fellowship), and the Council for Higher Education and Israel Academy of Sciences and Humanities (Excellence fellowship). C.A.W. acknowledges support from CIERA, the Adler Planetarium, and the Brinson Foundation through a CIERA-Adler postdoctoral fellowship. O.Y. is supported by the National Science Foundation Graduate Research Fellowship under grant No. DGE-2139292.

We thank the anonymous referee for careful review of our paper.

Contributions

We present the author list in alphabetical order in recognition that this paper is the result of the decades-long work of many people in the NANOGrav Collaboration. All authors contributed to the activities of the NANOGrav Collaboration, leading to the work presented here, and reviewed the manuscript, text, and figures prior to the paper submission. Specific author contributions are as follows. G.A., A.A., A.M.A., Z.A., P.T.B., P.R.B., H.T.C., K.C., M.E.D., P.B.D., T.D., E.C.F., W.F., E.F., G.E.F., N.G., P.A.G., J.G., D.C.G., J.S.H., R.J.J., M.L.J., D.L.K., M.K., M.T.L., D.R.L., J.L., R.S.L., A.M., M.A.M., N.M., B.W.M., C.N., D.J.N., P.N., T.T.P., B.B.P.P., N.S.P., H.A.R., S.M.R., P.S.R., A.S., C.S., B.J.S., I.H.S., K.S., A.S., J.K.S., and H.M.W. contributed through a combination of observations, arrival time calculations, data checks and refinements, and timing model development and analysis; additional specific contributions to the data set are summarized in G. Agazie et al. (2023a). R.B. ran the Bayesian detection and upper limit analysis and wrote the bulk of the paper. J.S. assisted in paper writing, analysis, and code debugging, and ran simulations for SNR scaling tests. B.B., J.S.H., J.T., and X.S. provided guidance on searches and analysis.

Files

Agazie_2025_ApJ_987_5.pdf

Files (2.3 MB)

Name	Size	Download all
Agazie_2025_ApJ_987_5.pdf md5:bf3bb18750c5fb81c08040725a0d5010	2.3 MB	Preview Download

Additional details

Is described by: Journal Issue: https://iopscience.iop.org/collections/apjl-230623-245-Focus-on-NANOGrav-15-year (URL)
Is new version of: Discussion Paper: arXiv:2502.18599 (arXiv)

National Science Foundation
1430284
National Science Foundation
2020265
Gordon and Betty Moore Foundation
National Science Foundation
2114721
Natural Sciences and Engineering Research Council
Canadian Institute for Advanced Research
National Science Foundation
AST-1744119
National Science Foundation
AST-1909933
Research Corporation for Science Advancement
27553
Science and Technology Facilities Council
ST/W000946/1
Alfred P. Sloan Foundation
National Science Foundation
1815664
Oregon State University
National Science Foundation
AST-2007993
Vanderbilt University
University of British Columbia
6456
United States Naval Research Laboratory
S-15633Y
National Science Foundation
2009468
National Aeronautics and Space Administration
80GSFC24M0006
National Science Foundation
PHY-2011772
National Science Foundation
2146016
California Institute of Technology
Jet Propulsion Laboratory
National Aeronautics and Space Administration
80NM0018D0004
National Science Foundation
1458952
National Science Foundation
2009425
National Science Foundation
PHY-1748958
National Science Foundation
AST-2106552
Deutsche Forschungsgemeinschaft
EXC 2121 390833306
University of Toronto
John Templeton Foundation
National Science Foundation
2207267
Eötvös Loránd University
National Science Foundation
2216793
Office of Naval Research
6.1 Basic Research Funding -
Texas Tech University
National Science Foundation
AST-2202388
National Science Foundation
1847938
Ben-Gurion University of the Negev

Council for Higher Education
Israel Academy of Sciences and Humanities
Adler Planetarium
Brinson Foundation
National Science Foundation
DGE-2139292

Accepted: 2025-05-12
Available: 2025-06-23

Published

Caltech groups: Division of Physics, Mathematics and Astronomy (PMA)
Publication Status: Published

	All versions	This version
Views	13	13
Downloads	5	5
Data volume	18.7 MB	18.7 MB

The NANOGrav 15 yr Data Set: Search for Gravitational-wave Memory

Copyright and License

Acknowledgement

Contributions

Files

Agazie_2025_ApJ_987_5.pdf

Files (2.3 MB)

Additional details

Related works

Funding

Dates

Caltech Custom Metadata

The NANOGrav 15 yr Data Set: Search for Gravitational-wave Memory

Creators

Abstract

Copyright and License

Acknowledgement

Contributions

Files

Agazie_2025_ApJ_987_5.pdf

Files (2.3 MB)

Additional details

Related works

Funding

Dates

Caltech Custom Metadata