Browse by author
Lookup NU author(s): Dr Anne ArchibaldORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2023. The Author(s). Published by the American Astronomical Society.Analyses of pulsar timing data have provided evidence for a stochastic gravitational wave background in the nanohertz frequency band. The most plausible source of this background is the superposition of signals from millions of supermassive black hole binaries. The standard statistical techniques used to search for this background and assess its significance make several simplifying assumptions, namely (i) Gaussianity, (ii) isotropy, and most often, (iii) a power-law spectrum. However, a stochastic background from a finite collection of binaries does not exactly satisfy any of these assumptions. To understand the effect of these assumptions, we test standard analysis techniques on a large collection of realistic simulated data sets. The data-set length, observing schedule, and noise levels were chosen to emulate the NANOGrav 15 yr data set. Simulated signals from millions of binaries drawn from models based on the Illustris cosmological hydrodynamical simulation were added to the data. We find that the standard statistical methods perform remarkably well on these simulated data sets, even though their fundamental assumptions are not strictly met. They are able to achieve a confident detection of the background. However, even for a fixed set of astrophysical parameters, different realizations of the universe result in a large variance in the significance and recovered parameters of the background. We also find that the presence of loud individual binaries can bias the spectral recovery of the background if we do not account for them.
Author(s): Becsy B, Cornish NJ, Meyers PM, Kelley LZ, Agazie G, Anumarlapudi A, Archibald AM, Arzoumanian Z, Baker PT, Blecha L, Brazier A, Brook PR, Burke-Spolaor S, Casey-Clyde JA, Charisi M, Chatterjee S, Chatziioannou K, Cohen T, Cordes JM, Crawford F, Cromartie HT, Crowter K, DeCesar ME, Demorest PB, Dolch T, Ferrara EC, Fiore W, Fonseca E, Freedman GE, Garver-Daniels N, Gentile PA, Glaser J, Good DC, Gultekin K, Hazboun JS, Hourihane S, Jennings RJ, Johnson AD, Jones ML, Kaiser AR, Kaplan DL, Kerr M, Key JS, Laal N, Lam MT, Lamb WG, W Lazio TJ, Lewandowska N, Littenberg TB, Liu T, Lorimer DR, Luo J, Lynch RS, Ma C-P, Madison DR, McEwen A, McKee JW, McLaughlin MA, McMann N, Meyers BW, Mingarelli CMF, Mitridate A, Ng C, Nice DJ, Ocker SK, Olum KD, Pennucci TT, Perera BBP, Pol NS, Radovan HA, Ransom SM, Ray PS, Romano JD, Sardesai SC, Schmiedekamp A, Schmiedekamp C, Schmitz K, Shapiro-Albert BJ, Siemens X, Simon J, Siwek MS, Sosa Fiscella SV, Stairs IH, Stinebring DR, Stovall K, Susobhanan A, Swiggum JK, Taylor SR, Turner JE, Unal C, Vallisneri M, van Haasteren R, Vigeland SJ, Wahl HM, Witt CA, Young O
Publication type: Article
Publication status: Published
Journal: Astrophysical Journal
Year: 2023
Volume: 959
Issue: 1
Print publication date: 10/12/2023
Online publication date: 29/11/2023
Acceptance date: 04/11/2023
Date deposited: 05/01/2024
ISSN (print): 0004-637X
ISSN (electronic): 1538-4357
Publisher: Institute of Physics
URL: https://doi.org/10.3847/1538-4357/ad09e4
DOI: 10.3847/1538-4357/ad09e4
Altmetrics provided by Altmetric
