NANOGrav 15-year gravitational-wave background methods
Creators: name: Johnson, Aaron D.
name: Meyers, Patrick M.
name: Baker, Paul T.
name: Cornish, Neil J.
name: Hazboun, Jeffrey S.
name: Littenberg, Tyson B.
name: Romano, Joseph D.
name: Taylor, Stephen R.
name: Vallisneri, Michele
name: Vigeland, Sarah J.
name: Olum, Ken D.
name: Siemens, Xavier
name: Ellis, Justin A.
name: van Haasteren, Rutger
name: Hourihane, Sophie
name: Agazie, Gabriella
name: Anumarlapudi, Akash
name: Archibald, Anne M.
name: Arzoumanian, Zaven
name: Blecha, Laura
name: Brazier, Adam
name: Brook, Paul R.
name: Burke-Spolaor, Sarah
name: Bécsy, Bence
name: Casey-Clyde, J. Andrew
name: Charisi, Maria
name: Chatterjee, Shami
name: Chatziioannou, Katerina
name: Cohen, Tyler
name: Cordes, James M.
name: Crawford, Fronefield
name: Cromartie, H. Thankful
name: Crowter, Kathryn
name: DeCesar, Megan E.
name: Demorest, Paul B.
name: Dolch, Timothy
name: Drachler, Brendan
name: Ferrara, Elizabeth C.
name: Fiore, William
name: Fonseca, Emmanuel
name: Freedman, Gabriel E.
name: Garver-Daniels, Nate
name: Gentile, Peter A.
name: Glaser, Joseph
name: Good, Deborah C.
name: Gültekin, Kayhan
name: Jennings, Ross J.
name: Jones, Megan L.
name: Kaiser, Andrew R.
name: Kaplan, David L.
name: Kelley, Luke Zoltan
name: Kerr, Matthew
name: Key, Joey S.
name: Laal, Nima
name: Lam, Michael T.
name: Lamb, William G.
name: Lazio, T. Joseph W.
name: Lewandowska, Natalia
name: Liu, Tingting
name: Lorimer, Duncan R.
name: Luo, Jing
name: Lynch, Ryan S.
name: Ma, Chung-Pei
name: Madison, Dustin R.
name: McEwen, Alexander
name: McKee, James W.
name: McLaughlin, Maura A.
name: McMann, Natasha
name: Meyers, Bradley W.
name: Mingarelli, Chiara M. F.
name: Mitridate, Andrea
name: Ng, Cherry
name: Nice, David J.
name: Ocker, Stella Koch
name: Pennucci, Timothy T.
name: Perera, Benetge B. P.
name: Pol, Nihan S.
name: Radovan, Henri A.
name: Ransom, Scott M.
name: Ray, Paul S.
name: Sardesai, Shashwat C.
name: Schmiedekamp, Carl
name: Schmiedekamp, Ann
name: Schmitz, Kai
name: Shapiro-Albert, Brent J.
name: Simon, Joseph
name: Siwek, Magdalena S.
name: Stairs, Ingrid H.
name: Stinebring, Daniel R.
name: Stovall, Kevin
name: Susobhanan, Abhimanyu
name: Swiggum, Joseph K.
name: Turner, Jacob E.
name: Unal, Caner
name: Wahl, Haley M.
name: Witt, Caitlin A.
name: Young, Olivia
name: NANOGrav Collaboration
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2024
Subjects: subject: 530

description: (2024). doi:10.1103/PhysRevD.109.103012
description: Pulsar timing arrays (PTAs) use an array of millisecond pulsars to search for gravitational waves in the nanohertz regime in pulse time of arrival data. This paper presents rigorous tests of PTA methods, examining their consistency across the relevant parameter space. We discuss updates to the 15-year isotropic gravitational-wave background analyses and their corresponding code representations. Descriptions of the internal structure of the flagship algorithms enterprise and ptmcmcsampler are given to facilitate understanding of the PTA likelihood structure, how models are built, and what methods are currently used in sampling the high-dimensional PTA parameter space. We introduce a novel version of the PTA likelihood that uses a two-step marginalization procedure that performs much faster in gravitational wave searches, reducing the required resources facilitating the computation of Bayes factors via thermodynamic integration and sampling a large number of realizations for computing Bayesian false-alarm probabilities. We perform stringent tests of consistency and correctness of the Bayesian and frequentist analysis methods. For the Bayesian analysis, we test prior recovery, simulation recovery, and Bayes factors. For the frequentist analysis, we test that the optimal statistic, when modified to account for a non-negligible gravitational-wave background, accurately recovers the amplitude of the background. We also summarize recent advances and tests performed on the optimal statistic in the literature from both gravitational wave background detection and parameter estimation perspectives. The tests presented here validate current analyses of PTA data.