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The NANOGrav 15yr Data Set: Search for Signals from New Physics

Afzal, Adeela; Agazie, Gabriella; Anumarlapudi, Akash; Archibald, Anne M.; Arzoumanian, Zaven; Baker, Paul T.; Bécsy, Bence; Blanco-Pillado, Jose Juan; Blecha, Laura; Boddy, Kimberly K.; Brazier, Adam; Brook, Paul R.; Burke-Spolaor, Sarah; Burnette, Rand; Case, Robin; Charisi, Maria; Chatterjee, Shami; Chatziioannou, Katerina; Cheeseboro, Belinda D.; Chen, Siyuan; Cohen, Tyler; Cordes, James M.; Cornish, Neil J.; Crawford, Fronefield; Cromartie, H. Thankful; Crowter, Kathryn; Cutler, Curt J.; DeCesar, Megan E.; DeGan, Dallas; Demorest, Paul B.; Deng, Heling; Dolch, Timothy; Drachler, Brendan; von Eckardstein, Richard; Ferrara, Elizabeth C.; Fiore, William; Fonseca, Emmanuel; Freedman, Gabriel E.; Garver-Daniels, Nate; Gentile, Peter A.; Gersbach, Kyle A.; Glaser, Joseph; Good, Deborah C.; Guertin, Lydia; Gültekin, Kayhan; Hazboun, Jeffrey S.; Hourihane, Sophie; Islo, Kristina; Jennings, Ross J.; Johnson, Aaron D.; Jones, Megan L.; Kaiser, Andrew R.; Kelley, Luke Zoltan; Kerr, Matthew;...


Adeela Afzal

Gabriella Agazie

Akash Anumarlapudi

Anne M. Archibald

Zaven Arzoumanian

Paul T. Baker

Bence Bécsy

Jose Juan Blanco-Pillado

Laura Blecha

Kimberly K. Boddy

Adam Brazier

Paul R. Brook

Sarah Burke-Spolaor

Rand Burnette

Robin Case

Maria Charisi

Shami Chatterjee

Katerina Chatziioannou

Belinda D. Cheeseboro

Siyuan Chen

Tyler Cohen

James M. Cordes

Neil J. Cornish

Fronefield Crawford

H. Thankful Cromartie

Kathryn Crowter

Curt J. Cutler

Megan E. DeCesar

Dallas DeGan

Paul B. Demorest

Heling Deng

Timothy Dolch

Brendan Drachler

Richard von Eckardstein

Elizabeth C. Ferrara

William Fiore

Emmanuel Fonseca

Gabriel E. Freedman

Nate Garver-Daniels

Peter A. Gentile

Kyle A. Gersbach

Joseph Glaser

Deborah C. Good

Lydia Guertin

Kayhan Gültekin

Jeffrey S. Hazboun

Sophie Hourihane

Kristina Islo

Ross J. Jennings

Aaron D. Johnson

Megan L. Jones

Andrew R. Kaiser

Luke Zoltan Kelley

Matthew Kerr

Joey S. Key

Nima Laal

Michael T. Lam

David L. Kaplan

Joseph T.W. Lazio

Vincent S.H. Lee

Natalia Lewandowska

Rafael R. Lino dos Santos

Tyson B. Littenberg

William G. Lamb

Tingting Liu

Duncan R. Lorimer

Jing Luo

Ryan S. Lynch

Chung Pei Ma

Alexander McEwen

Dustin R. Madison

Maura A. McLaughlin

Natasha McMann

Bradley W. Meyers

Patrick M. Meyers

Chiara M.F. Mingarelli

Andrea Mitridate

Jonathan Nay

Priyamvada Natarajan

Cherry Ng

David J. Nice

Stella Koch Ocker

Ken D. Olum

Timothy T. Pennucci

Benetge B.P. Perera

Polina Petrov

Nihan S. Pol

Henri A. Radovan

Scott M. Ransom

Paul S. Ray

Joseph D. Romano

Shashwat C. Sardesai

Ann Schmiedekamp

Carl Schmiedekamp

Kai Schmitz

Tobias Schröder

Levi Schult

Brent J. Shapiro-Albert

Xavier Siemens


The 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence for the presence of a low-frequency gravitational-wave (GW) background. In this paper, we investigate potential cosmological interpretations of this signal, specifically cosmic inflation, scalar-induced GWs, first-order phase transitions, cosmic strings, and domain walls. We find that, with the exception of stable cosmic strings of field theory origin, all these models can reproduce the observed signal. When compared to the standard interpretation in terms of inspiraling supermassive black hole binaries (SMBHBs), many cosmological models seem to provide a better fit resulting in Bayes factors in the range from 10 to 100. However, these results strongly depend on modeling assumptions about the cosmic SMBHB population and, at this stage, should not be regarded as evidence for new physics. Furthermore, we identify excluded parameter regions where the predicted GW signal from cosmological sources significantly exceeds the NANOGrav signal. These parameter constraints are independent of the origin of the NANOGrav signal and illustrate how pulsar timing data provide a new way to constrain the parameter space of these models. Finally, we search for deterministic signals produced by models of ultralight dark matter (ULDM) and dark matter substructures in the Milky Way. We find no evidence for either of these signals and thus report updated constraints on these models. In the case of ULDM, these constraints outperform torsion balance and atomic clock constraints for ULDM coupled to electrons, muons, or gluons.


Afzal, A., Agazie, G., Anumarlapudi, A., Archibald, A. M., Arzoumanian, Z., Baker, P. T., …Siemens, X. (2023). The NANOGrav 15yr Data Set: Search for Signals from New Physics. Astrophysical journal. Letters, 951(1), Article L11.

Journal Article Type Article
Acceptance Date Jun 7, 2023
Online Publication Date Jun 29, 2023
Publication Date Jul 1, 2023
Deposit Date Jul 14, 2023
Publicly Available Date Aug 14, 2023
Journal Astrophysical Journal Letters
Print ISSN 2041-8205
Electronic ISSN 2041-8213
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 951
Issue 1
Article Number L11
Public URL


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Copyright Statement
© 2023. 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.

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