Abstract
In order to estimate cosmic curvature from cosmological probes like standard candles, one has to measure the luminosity distance D_L(z), its derivative with respect to redshift D'_L(z) and the expansion rate H(z) at the same redshift. In this paper, we study how such idea could be implemented with future generation of space-based DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO), in combination with cosmic chronometers providing cosmology-independent H(z) data. Our results show that for the Hubble diagram of simulated DECIGO data acting as a new type of standard siren, it would be able to constrain cosmic curvature with the precision of varDelta varOmega _k= 0.09 with the currently available sample of 31 measurements of Hubble parameters. In the framework of the third generation ground-based gravitational wave detectors, the spatial curvature is constrained to be varDelta varOmega _k= 0.13 for Einstein Telescope (ET). More interestingly, compared to other approaches aiming for model-independent estimations of spatial curvature, our analysis also achieve the reconstruction of the evolution of varOmega _k(z), in the framework of a model-independent method of Gaussian processes (GP) without assuming a specific form. Therefore, one can expect that the newly emerged gravitational wave astronomy can become useful in local measurements of cosmic curvature using distant sources.
Highlights
Dicts that the radius of curvature of the Universe should be very large, which means that cosmic curvature should be close to zero [3]
It is fully consistent with the vanishing curvature – an assumption underlying our gravitational wave (GW) data simulations and compatible with the constraints obtained from the latest Planck cosmic microwave background (CMB) measurements [4]
One was able to directly calculate the curvature parameter Ωk combining these results with the expansion rate H (z) measurements obtained from a sample of cosmic chronometers
Summary
Dicts that the radius of curvature of the Universe should be very large, which means that cosmic curvature should be close to zero [3]. The distance sum rule [12], which characterizes the relation between the distances of the background source, the lens and the observer in the Friedmann–Lemaître– Robertson–Walker (FLRW) metric, has been proposed as a model-independent method to constrain the curvature of the Universe [13] Such methodology was applied to test the validity to FLRW metric, based on the galactic-scale lensing systems where strongly lensed gravitational waves and their. Qi et al [14], Zhou et al [15] extended the cosmic curvature analysis to higher redshift, using the latest data sets of strong lensing systems [16,17] combined with intermediate-luminosity quasars calibrated as standard rulers [18] Another straightforward method to constrain the cosmic curvature has been proposed by Clarkson et al [6], using the expansion rate measurements H(z) and the transverse comoving distances D(z).
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