The NANOGrav 15 yr Dataset: Targeted Searches for Supermassive Black Hole Binaries
Abstract We present the first targeted searches for continuous gravitational waves (CWs) from 114 active galactic nuclei that may host supermassive black hole binaries, using the NANOGrav 15 yr dataset. By incorporating electromagnetic priors on sky location, distance, redshift, and CW frequency, our strain and chirp-mass upper limits are typically improved by a factor of ∼2 (median 2.2) relative to all-sky limits at the same frequency. Bayesian comparisons against a model including only a Hellings–Downs-correlated background disfavors a CW signal for all targets, with a mean Bayes factor of 0.73 ± 0.32. Two targets have Bayes factors slightly above unity, but coherence tests, random-targeting experiments, and a conservative accounting of the 114-target trials factor all indicate that they are consistent with noise. We use these two candidates as worked examples to illustrate an end-to-end targeted CW search analysis and a suite of follow-up tests that future promising candidates would need to pass. We find that the electromagnetic interpretations of both candidates are ambiguous, and we update the constraints on a putative binary in 3C 66B, ruling out part of its previously allowed parameter space. Ultimately, our results demonstrate the current sensitivity of targeted pulsar timing array searches for CWs and define a road map for future multimessenger CW detections.
Authors
- Nikita Agarwal (ORCID: https://orcid.org/0000-0001-7544-7876)
- Bjorn Larsen (ORCID: https://orcid.org/0000-0001-6436-8216)
- Sarah J. Vigeland (ORCID: https://orcid.org/0000-0003-4700-9072)
- Carl Schmiedekamp (ORCID: https://orcid.org/0000-0002-1283-2184)
- S. M. Ransom (ORCID: https://orcid.org/0000-0001-5799-9714)
- Akash Anumarlapudi (ORCID: https://orcid.org/0000-0002-8935-9882)
- J. G. Baier (ORCID: https://orcid.org/0000-0002-4972-1525)
- Emiko C. Gardiner (ORCID: https://orcid.org/0000-0002-8857-613X)
- Anne M. Archibald (ORCID: https://orcid.org/0000-0003-0638-3340)
- Caitlin Witt
- William Fiore (ORCID: https://orcid.org/0000-0001-5645-5336)
- Gabriel E. Freedman (ORCID: https://orcid.org/0000-0001-7624-4616)
- Michael T. Lam (ORCID: https://orcid.org/0000-0003-0721-651X)
- Deborah C. Good (ORCID: https://orcid.org/0000-0003-1884-348X)
- Olivia Young (ORCID: https://orcid.org/0000-0002-0883-0688)
- Abhimanyu Susobhanan (ORCID: https://orcid.org/0000-0002-2820-0931)
- J. A. Turner
- Peter A. Gentile (ORCID: https://orcid.org/0000-0001-8158-683X)
- Cayenne Matt (ORCID: https://orcid.org/0000-0002-9710-6527)
- Kathryn Crowter (ORCID: https://orcid.org/0000-0002-1529-5169)
- Robin Case (ORCID: https://orcid.org/0009-0007-4346-8921)
- P. T. Baker (ORCID: https://orcid.org/0000-0003-2745-753X)
- Paul R. Brook (ORCID: https://orcid.org/0000-0003-3053-6538)
- Andrea Mitridate (ORCID: https://orcid.org/0000-0003-2898-5844)
- Ann Schmiedekamp (ORCID: https://orcid.org/0000-0003-4391-936X)
- K. Wilson (ORCID: https://orcid.org/0000-0003-4231-2822)
- E Eisenberg (ORCID: https://orcid.org/0009-0007-0974-1891)
- Daniel R. Stinebring (ORCID: https://orcid.org/0000-0002-1797-3277)
- Paul S. Ray (ORCID: https://orcid.org/0000-0002-5297-5278)
- Benetge B. P. Perera (ORCID: https://orcid.org/0000-0002-8509-5947)
- Megan L. Jones (ORCID: https://orcid.org/0000-0001-6607-3710)
- P. M. Meyers (ORCID: https://orcid.org/0000-0002-2689-0190)
- Jacob E. Turner (ORCID: https://orcid.org/0000-0002-2451-7288)
- Stella Koch Ocker (ORCID: https://orcid.org/0000-0002-4941-5333)
- Tyler Cohen
- Joseph K. Swiggum (ORCID: https://orcid.org/0000-0002-1075-3837)
- H. A. Radovan (ORCID: https://orcid.org/0000-0002-2074-4360)
- Rand Burnette (ORCID: https://orcid.org/0009-0008-3649-0618)
- Federico Semenzato
- Justin A. Ellis (ORCID: https://orcid.org/0000-0003-1715-974X)
- Jacob Taylor
- Megan DeCesar
- Laura Blecha
- Haley M. Wahl
- J. Andrew Casey-Clyde
- Ryan S. Lynch
- Natasha McMann
- Michele Vallisneri
- Sophia V. Sosa Fiscella
- Joseph Glaser
- David J. Nice
- Priyamvada Natarajan
- Kevin Stovall
- Alexander Saffer
- Shashwat C. Sardesai
- Jeffrey S. Hazboun
- Matthew J. Graham
- Lankeswar Dey
- H. Thankful Cromartie
- Gabriella Agazie
- Tingting Liu
- Natalia Lewandowska
- Yu-Ting Chang
- T. Joseph W. Lazio
- Jing Luo
- Bradley W. Meyers
- Nima Laal
- James W. McKee
- Qinyuan Zheng
- Forrest Hutchison
- Chiara M. F. Mingarelli
- London E. Willson
- Rohan Shivakumar
- Heling Deng
- Timothy Dolch
- David L. Kaplan
- Emmanuel Fonseca
- Ken D. Olum
- Paolo Coppi
- Joseph D. Romano
- Brent J. Shapiro-Albert
- James M. Cordes
- Stephen R. Taylor
- Aaron D. Johnson
- Ingrid H. Stairs
- Paul B. Demorest
- Nihan S. Pol
- Kayhan Gültekin
- Luke Zoltan Kelley
- Duncan R. Lorimer
- C. J. Harris
- Rutger van Haasteren
- David Wright
- Mercedes S. Thompson
- Dustin R. Madison
- William G. Lamb
- Fronefield Crawford
- Maura A. McLaughlin
- Polina Petrov
- Zaven Arzoumanian
- Chung-Pei Ma
- Elizabeth C. Ferrara
- Kai Schmitz
- Shami Chatterjee
- Daniel J. D'Orazio
- Joseph Simon
- Bence Becsy
- Cherry Ng
- Nate Garver-Daniels
- Sarah Burke-Spolaor
- Neil J. Cornish
- Alexander McEwen
- Joey S. Key
- Timothy T. Pennucci
- Kyle A. Gersbach
- Adam Brazier
- Matthew Kerr
- Xavier Siemens
Publication Details
- Journal
- The Astrophysical Journal Letters
- Published
- 2026-02-05
- DOI
- https://doi.org/10.3847/2041-8213/ae3719
- Citations
- 5
- Primary Topic
- Pulsars and Gravitational Waves Research
- Type
- article
- Field-Weighted Citation Impact
- 119.13