We present new limits on an isotropic stochastic gravitational-wave background (GWB) using a six pulsar data set spanning 18 yr of observations from the 2015 European Pulsar Timing Array data release. Performing a Bayesian analysis, we fit simultaneously for the intrinsic noise parameters for each pulsar, along with common correlated signals including clock, and Solar system ephemeris errors, obtaining a robust 95 per cent upper limit on the dimensionless strain amplitude A of the background of A < 3.0 × 10-15 at a reference frequency of 1 yr-1 and a spectral index of 13/3, corresponding to a background from inspiralling supermassive black hole binaries, constraining the GWenergy density to Ωgw(f)h2 < 1.1 × 10-9 at 2.8 nHz. We also present limits on the correlated power spectrum at a series of discrete frequencies, and showthat our sensitivity to a fiducial isotropic GWB is highest at a frequency of~5 × 10-9 Hz. Finally, we discuss the implications of our analysis for the astrophysics of supermassive black hole binaries, and present 95 per cent upper limits on the string tension, Gμ/c2, characterizing a background produced by a cosmic string network for a set of possible scenarios, and for a stochastic relic GWB. For a Nambu-Goto field theory cosmic string network, we set a limit Gμ/c2 < 1.3 × 10-7, identical to that set by the Planck Collaboration, when combining Planck and high-ℓ cosmic microwave background data from other experiments. For a stochastic relic background, we set a limit of Ωgwrelic (f)h2 < 1.2 × 10-9, a factor of 9 improvement over the most stringent limits previously set by a pulsar timing array.

Lentati, L., Taylor, S., Mingarelli, C., Sesana, A., Sanidas, S., Vecchio, A., et al. (2015). European Pulsar Timing Array limits on an isotropic stochastic gravitational-wave background. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 453(3), 2576-2598 [10.1093/mnras/stv1538].

European Pulsar Timing Array limits on an isotropic stochastic gravitational-wave background

Sesana A.;
2015

Abstract

We present new limits on an isotropic stochastic gravitational-wave background (GWB) using a six pulsar data set spanning 18 yr of observations from the 2015 European Pulsar Timing Array data release. Performing a Bayesian analysis, we fit simultaneously for the intrinsic noise parameters for each pulsar, along with common correlated signals including clock, and Solar system ephemeris errors, obtaining a robust 95 per cent upper limit on the dimensionless strain amplitude A of the background of A < 3.0 × 10-15 at a reference frequency of 1 yr-1 and a spectral index of 13/3, corresponding to a background from inspiralling supermassive black hole binaries, constraining the GWenergy density to Ωgw(f)h2 < 1.1 × 10-9 at 2.8 nHz. We also present limits on the correlated power spectrum at a series of discrete frequencies, and showthat our sensitivity to a fiducial isotropic GWB is highest at a frequency of~5 × 10-9 Hz. Finally, we discuss the implications of our analysis for the astrophysics of supermassive black hole binaries, and present 95 per cent upper limits on the string tension, Gμ/c2, characterizing a background produced by a cosmic string network for a set of possible scenarios, and for a stochastic relic GWB. For a Nambu-Goto field theory cosmic string network, we set a limit Gμ/c2 < 1.3 × 10-7, identical to that set by the Planck Collaboration, when combining Planck and high-ℓ cosmic microwave background data from other experiments. For a stochastic relic background, we set a limit of Ωgwrelic (f)h2 < 1.2 × 10-9, a factor of 9 improvement over the most stringent limits previously set by a pulsar timing array.
Articolo in rivista - Articolo scientifico
Gravitational waves; Methods: data analysis; Pulsars: general
English
2015
453
3
2576
2598
reserved
Lentati, L., Taylor, S., Mingarelli, C., Sesana, A., Sanidas, S., Vecchio, A., et al. (2015). European Pulsar Timing Array limits on an isotropic stochastic gravitational-wave background. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 453(3), 2576-2598 [10.1093/mnras/stv1538].
File in questo prodotto:
File Dimensione Formato  
stv1538.pdf

Solo gestori archivio

Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 1.61 MB
Formato Adobe PDF
1.61 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/290599
Citazioni
  • Scopus 383
  • ???jsp.display-item.citation.isi??? 367
Social impact