The MeerKAT Pulsar Timing Array: The first search for gravitational waves with the MeerKAT radio telescope - Archive ouverte HAL
Article Dans Une Revue Mon.Not.Roy.Astron.Soc. Année : 2025

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

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

Résumé

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 ($\sim$2-4$\sigma$). In this paper we present the results of background searches with the MeerKAT Pulsar Timing Array. Although of limited duration (4.5 yr), the $\sim$ 250,000 arrival times with a median error of just $3 \mu$s 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 (3-3.4$\sigma$) 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 $h_{c, {\rm yr}} = 7.5^{+0.8}_{-0.9} \times 10^{-15}$ measured at a spectral index of $\alpha=-0.26$, decreasing to $h_{c, {\rm yr}} = 4.8^{+0.8}_{-0.9} \times 10^{-15}$ when assessed at the predicted $\alpha=-2/3$. 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.

Dates et versions

hal-04821144 , version 1 (05-12-2024)

Identifiants

Citer

Matthew T Miles, Ryan M Shannon, Daniel J Reardon, Matthew Bailes, David J Champion, et al.. The MeerKAT Pulsar Timing Array: The first search for gravitational waves with the MeerKAT radio telescope. Mon.Not.Roy.Astron.Soc., 2025, 536 (2), pp.1489-1500. ⟨10.1093/mnras/stae2571⟩. ⟨hal-04821144⟩
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