Measuring the primordial gravitational waves from cosmic microwave background and stochastic gravitational wave background observations

Abstract

We constrain the primordial gravitational waves from cosmic microwave background (CMB) and stochastic gravitational wave background (SGWB) observations. SGWB provides the latest way to explore the early universe and the cosmological evolution which can be reflected by primordial gravitational waves. We not only combine LIGO observations with CMB to measure primordial gravitational waves, but also forecast the potential abilities of the LISA detector and PTA projects. In the $\Lambda$CDM+$r$+$n_t$ model, the standard six parameters change slightly from SGWB observations. While the constraints on tensor-to-scalar ratio and tensor spectral index are improved obviously from SGWB observations. FAST projects have a significant impact on tensor-to-scalar ratio and tensor spectral index, namely $r<0.028$ and $n_t=-0.41_{-0.96}^{+0.64}$ at $95\%$ confidence level.

References in corpus (6)

• The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15
• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) Project
• Observational Constraints on Theories with a Blue Spectrum of Tensor Modes
• No evidence for the blue-tilted power spectrum of relic gravitational waves
• Measuring the scalar induced gravitational waves from observations

Cited by in corpus (2)

• Measuring the primordial curvature perturbations from the scalar induced gravitational waves
• Measuring the speed of scalar induced gravitational waves from observations