| Title: |
The NANOGrav 15 yr Dataset: Targeted Searches for Supermassive Black Hole Binaries |
| Authors: |
Agarwal, Nikita; 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; Case, Robin; Casey-Clyde, J. Andrew; Chang, Yu-Ting; Charisi, Maria; Chatterjee, Shami; Cohen, Tyler; Coppi, Paolo; 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; D'Orazio, Daniel J.; Eisenberg, Ellis; Ferrara, Elizabeth C.; Doskoch, Graham; Fiore, William; Fonseca, Emmanuel; Freedman, Gabriel E.; Gardiner, Emiko C.; Garver-Daniels, Nate; Gentile, Peter A.; Gersbach, Kyle A.; Glaser, Joseph; Graham, Matthew J.; Good, Deborah C.; Gültekin, Kayhan; Harris, C. J.; Hazboun, Jeffrey S.; Hutchison, Forrest; 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.; Matt, Cayenne; 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.; Nichols, Shania; 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.; Romano, Joseph D.; Runnoe, Jessie C.; Saffer, Alexander; Sardesai, Shashwat C.; Schmiedekamp, Ann; Schmiedekamp, Carl; Schmitz, Kai; Semenzato, Federico; Shapiro-Albert, Brent J.; Shivakumar, Rohan; Siemens, Xavier; Simon, Joseph; Sosa Fiscella, Sophia V.; Stairs, Ingrid H.; Stinebring, Daniel R.; Stovall, Kevin; Susobhanan, Abhimanyu; Swiggum, Joseph K.; Taylor, Jacob A.; Taylor, Stephen R.; Thompson, Mercedes S.; Turner, Jacob E.; Vallisneri, Michele; van Haasteren, Rutger; Vigeland, Sarah J.; Wahl, Haley M.; Willson, London; Wilson, Kevin P.; Witt, Caitlin A.; Wright, David; Young, Olivia; Zheng, Qinyuan; The NANOGrav Collaboration |
| Source: |
Astrophysical Journal Letters, 998(1), L11, (2026-02-10) |
| Publisher Information: |
American Astronomical Society |
| Publication Year: |
2026 |
| Collection: |
Caltech Authors (California Institute of Technology) |
| Subject Terms: |
Gravitational waves |
| Description: |
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. ; © 2026. 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. ; C.M.F.M. thanks F. van den Bosch, B. Farr, J. Greene, K. Grunthal, D. Holz, N. Navon, V. Ozoliņš, T. A. Prince, C. M. Urry, and A. Vecchio. 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 numbers 1430284 and 2020265, the ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
https://arxiv.org/abs/arXiv:2508.16534; https://doi.org/10.5281/zenodo.17289574; https://authors.library.caltech.edu/communities/caltechauthors/ |
| DOI: |
10.3847/2041-8213/ae3719 |
| Availability: |
https://doi.org/10.3847/2041-8213/ae3719 |
| Rights: |
info:eu-repo/semantics/openAccess ; Creative Commons Attribution 4.0 International ; https://creativecommons.org/licenses/by/4.0/legalcode |
| Accession Number: |
edsbas.8FC5DDB3 |
| Database: |
BASE |