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.
Citazione: | 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. |
Tipo: | Articolo in rivista - Articolo scientifico |
Carattere della pubblicazione: | Scientifica |
Presenza di un coautore afferente ad Istituzioni straniere: | Si |
Titolo: | European Pulsar Timing Array limits on an isotropic stochastic gravitational-wave background |
Autori: | Lentati, L; Taylor, S; Mingarelli, C; Sesana, A; Sanidas, S; Vecchio, A; Caballero, R; Lee, K; van Haasteren, R; Babak, S; Bassa, C; Brem, P; Burgay, M; Champion, D; Cognard, I; Desvignes, G; Gair, J; Guillemot, L; Hessels, J; Janssen, G; Karuppusamy, R; Kramer, M; Lassus, A; Lazarus, P; Liu, K; Oslowski, S; Perrodin, D; Petiteau, A; Possenti, A; Purver, M; Rosado, P; Smits, R; Stappers, B; Theureau, G; Tiburzi, C; Verbiest, J |
Autori: | |
Data di pubblicazione: | 2015 |
Lingua: | English |
Rivista: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1093/mnras/stv1538 |
Appare nelle tipologie: | 01 - Articolo su rivista |