English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background

MPS-Authors
/persons/resource/persons2713

Sesana,  Alberto
Astrophysical Relativity, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;

/persons/resource/persons20655

Babak,  Stanislav
Astrophysical Relativity, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;

Brem,  Patrick
Astrophysical Relativity, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;

Locator
There are no locators available
Fulltext (public)

1504.03692.pdf
(Preprint), 7MB

Supplementary Material (public)
There is no public supplementary material available
Citation

Lentati, L., Taylor, S. R., Mingarelli, C. M. F., Sesana, A., Sanidas, S. A., 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. doi:10.1093/mnras/stv1538.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0027-7CEA-E
Abstract
We present new limits on an isotropic stochastic gravitational-wave background (GWB) using a six pulsar dataset spanning 18 yr of observations from the 2015 European Pulsar Timing Array data release (Desvignes et al. in prep.). Performing a Bayesian analysis, we fit simultaneously for the intrinsic noise parameters for each pulsar in this dataset, along with common correlated signals including clock, and Solar System ephemeris errors to obtain a robust 95$\%$ upper limit on the dimensionless strain amplitude $A$ of the background of $A<3.0\times 10^{-15}$ at a reference frequency of $1\mathrm{yr^{-1}}$ and a spectral index of $13/3$, corresponding to a background from inspiralling super-massive black hole binaries, constraining the GW energy density to $\Omega_\mathrm{gw}(f)h^2 < 1.1\times10^{-9}$ at 2.8 nHz. We show that performing such an analysis when fixing the intrinsic noise parameters for the individual pulsars leads to an erroneously stringent upper limit, by a factor $\sim 1.7$. We obtain a difference in the logarithm of the Bayesian evidence between models that include either a correlated background, or uncorrelated common red noise of $-1.0 \pm 0.5$, indicating no support for the presence of a correlated GWB in this dataset. We discuss the implications of our analysis for the astrophysics of supermassive black hole binaries, and present 95$\%$ upper limits on the string tension, $G\mu/c^2$, characterising 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 $G\mu/c^2<1.3\times10^{-7}$, identical to that set by the Planck Collaboration, combining Planck and high-$\ell$ Cosmic Microwave Background data from other experiments. (Abridged)