Constraints on cosmic string tension imposed by the limit on the stochastic gravitational wave background from the European Pulsar Timing Array

By S. Sanidas, R. Battye, B. Stappers. 2012

134 citations recorded by the source corpus.

We investigate the constraints that can be placed on the cosmic string tension by using the current pulsar timing array (PTA) limits on the gravitational wave background. We have developed a code to compute the spectrum of gravitational waves (GWs) based on the widely accepted one-scale model. In its simplest form the one-scale model for cosmic strings allows one to vary: (i) the string tension, G mu/c(2); (ii) the size of cosmic string loops relative to the horizon at birth, alpha; (iii) the spectral index of the emission spectrum, q; (iv) the cutoff in the emission spectrum, n(*); and (v) the intercommutation probability, p. The amplitude and slope of the spectrum in the nHz frequency range is very sensitive to these unknown parameters. We have also investigated the impact of more complicated scenarios with multiple initial loop sizes alpha, in particular, the 2-alpha models proposed in the literature and a log-normal distribution for alpha. We have computed the constraint on G mu/c(2) due to the limit on a stochastic background of GWs imposed by the European Pulsar Timing Array. Taking into account all the possible uncertainties in the parameters we find a conservative upper limit of G mu/c(2) > Gamma G mu/c(2). This limit is less stringent than the previously published limits which are based on cusp emission, an approach which does not necessarily model all the possible uncertainties. We discuss the prospects for lowering this limit by 2 orders of magnitude, or even a detection of the GW background, in the very near future in the context of the Large European Array for Pulsars and the Square Kilometre Array.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5da5d02193582601e6a52d6ebe92a6bf262bbd05

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Citations in the corpus

Beyond the Standard Models with cosmic strings (2019, background): “OGrav, G. 5:3 10 11 [120]. Comparison with the theoretical predictions from the SGWB from cosmic strings leads to G. 2 10 11 [22,106] or G. 10 10 [110], even though it can be relaxed to G. 5 10 7 [38], after taking into account uncertainties on the loop size at formation and on the number of emittin”
Expected properties of the first gravitational wave signal detected with pulsar timing arrays (2015, background): “…are the GWs emitted by supermassive black hole (SBH) binaries (SBHBs; see, e.g., Sesana et al. 2008), although processes in the early Universe may also produce GWs in the same frequency band, like cosmic strings (Sanidas et al. 2012) or the cosmological QCD phase transition (Caprini et al. 2010).”
The NANOGrav 11-year Data Set: High-precision Timing of 45 Millisecond Pulsars (2017, background): “…al. 2015a), primordial gravitational waves from inflation (Grishchuk 1976, 1977; Starobinsky 1980; Lentati et al. 2015; Lasky et al. 2016), and gravitational waves originating from cosmic strings (e.g., Kibble 1976; Vilenkin 1981; Sanidas et al. 2012; Arzoumanian et al. 2015a; Lentati et al. 2015).”
European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background (2015, methodology): “We note the significant improvement of the EPTA result in comparison to that presented in Sanidas et al. (2012), which was ∼3 times less constraining than the best available limit at that time, set by the Wilkinson Microwave Anisotropy Probe 7-yr+ACT results.”
Probing the gravitational wave background from cosmic strings with LISA (2019, methodology): “The peak frequency scales approximately as [95]16”
The Parkes Pulsar Timing Array Project (2006, background): “Improved data sets should enable the detection and study of individual GW sources, for example, bright black hole binaries (Sesana et al. 2009) or burst signals from cosmic strings (Damour & Vilenkin 2005; Sanidas et al. 2012).”
The European Pulsar Timing Array and the Large European Array for Pulsars (2013, methodology): “…the EPTA investigated the constraints that can be placed on the tension of potentially existing cosmic strings, Gμ/c2, by using the EPTA limit: Sanidas et al (2012) presented a conservative upper limit of Gμ/c2 5.3 × 10−7 which typically occurs when the loop production scale is close to…”