The MeerKAT Pulsar Timing Array: The first search for gravitational waves with the MeerKAT radio telescope

作     者：Miles, Matthew T. Shannon, Ryan M. Reardon, Daniel J. Bailes, Matthew Champion, David J. Geyer, Marisa Gitika, Pratyasha Grunthal, Kathrin Keith, Michael J. Kramer, Michael Kulkarni, Atharva D. Nathan, Rowina S. Parthasarathy, Aditya Singha, Jaikhomba Theureau, Gilles Thrane, Eric Abbate, Federico Buchner, Sarah Cameron, Andrew D. Camilo, Fernando Moreschi, Beatrice E. Shaifullah, Golam Shamohammadi, Mohsen Possenti, Andrea Krishnan, Vivek Venkatraman 

作者机构：Centre for Astrophysics and Supercomputing Swinburne University of Technology PO Box 218 HawthornVIC3122 Australia The ARC Centre of Excellence for Gravitational Wave Discovery MPI für Radioastronomie Auf dem Hügel 69 Bonn53121 Germany Group Department of Mathematics and Applied Mathematics University of Cape Town Cape Town7700 South Africa Jodrell Bank Centre for Astrophysics University of Manchester Alan-Turing Building Oxford Street ManchesterM13 9PL United Kingdom School of Physics and Astronomy Monash University ClaytonVIC3800 Australia ASTRON Netherlands Institute for Radio Astronomy Oude Hoogeveensedijk 4 Dwingeloo7991 PD Netherlands Anton Pannekoek Institute for Astronomy University of Amsterdam Science Park 904 Amsterdam1098 XH Netherlands Laboratoire de Physique et Chimie de l’Environnement et de l’Espace LPC2E UMR7328 Université d’Orléans CNRS CNES OSUC Observatoire de Paris OrléansF-45071 France Laboratoire Univers et Théories Observatoire de Paris Université PSL Université de Paris Cité CNRS MeudonF-92190 France I-09047 Italy South African Radio Astronomy Observatory 2 Fir Street Black River Park Observatory7925 South Africa Dipartimento di Fisica "G. Occhialini" Universitá degli Studi di Milano-Bicocca Piazza della Scienza 3 MilanoI-20126 Italy 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2024年

核心收录：

主　　题：Pulsars 

摘      要：Pulsar Timing Arrays search for nanohertz-frequency gravitational waves by regularly observing ensembles of millisecond pulsars over many years to look for correlated timing residuals. Recently the first evidence for a stochastic gravitational wave background has been presented by the major Arrays, with varying levels of significance (∼2-4σ). In this paper we present the results of background searches with the MeerKAT Pulsar Timing Array. Although of limited duration (4.5 yr), the ∼ 250,000 arrival times with a median error of just 3πs on 83 pulsars make it very sensitive to spatial correlations. Detection of a gravitational wave background requires careful modelling of noise processes to ensure that any correlations represent a fit to the underlying background and not other misspecified processes. Under different assumptions about noise processes we can produce either what appear to be compelling Hellings-Downs correlations of high significance (3-3.4σ) with a spectrum close to that which is predicted, or surprisingly, under slightly different assumptions, ones that are insignificant. This appears to be related to the fact that many of the highest precision MeerKAT Pulsar Timing Array pulsars are in close proximity and dominate the detection statistics. The sky-averaged characteristic strain amplitude of the correlated signal in our most significant model is ℎcyr = 7.5+−0.90.8 × 10−15 measured at a spectral index of α = −0.26, decreasing to ℎcyr = 4.8+0.8−0.9 × 10−15 when assessed at the predicted α = −2/3. These data will be valuable as the International Pulsar Timing Array project explores the significance of gravitational wave detections and their dependence on the assumed noise models. Copyright © 2024, The Authors. All rights reserved.