Measuring the scalar induced gravitational waves from observations

TL;DR

This paper constrains scalar induced gravitational waves using CMB and gravitational wave data, revealing how different power spectrum models influence cosmological parameters and highlighting FAST's impact on tensor-to-scalar ratio.

Contribution

It provides new constraints on scalar induced gravitational waves from multiple observational datasets within the $$CDM+$r$ model, considering different power spectrum scenarios.

Findings

Constraints on cosmological parameters vary with power spectrum assumptions.

FAST data significantly impacts tensor-to-scalar ratio estimates.

Comparative analysis across LIGO, LISA, IPTA, and FAST datasets.

Abstract

We measure the scalar induced gravitational waves from the cosmic microwave background (CMB) observations and the gravitational wave observations. In the $\Lambda$CDM+$r$ model, we constrain the cosmological parameters within the evolution of the scalar induced gravitational waves by the additional scalar power spectrum. The two special cases called narrow power spectrum and wide power spectrum have influence on the cosmological parameters, especially the combinations of Planck18+BAO+BK15+LISA. We also compare these numerical results from four datasets within LIGO, LISA, IPTA and FAST projects, respectively. The constraints from FAST have a significant impact on tensor-to-scalar ratio.