How can gravitationalwave standard sirens and 21cm intensity mapping jointly provide a precise lateuniverse cosmological probe?
Abstract
In the next decades, the gravitationalwave (GW) standard siren observations and the neutral hydrogen 21cm intensity mapping (IM) surveys, as two promising cosmological probes, will play an important role in precisely measuring cosmological parameters. In this work, we make a forecast for cosmological parameter estimation with the synergy between the GW standard siren observations and the 21cm IM surveys. We choose the Einstein Telescope (ET) and the Taiji observatory as the representatives of the GW detection projects and choose the Square Kilometre Array (SKA) phase I midfrequency array as the representative of the 21cm IM experiments. In the simulation of the 21cm IM data, we assume perfect foreground removal and calibration. We find that the synergy of the GW standard siren observations and the 21cm IM survey could break the cosmological parameter degeneracies. The joint ET +Taiji +SKA data give σ (H_{0})=0.28 km s^{1} Mpc^{1} in the Λ CDM model, σ (w )=0.028 in the w CDM model, which are better than the results of P l a n c k +BAO +SNe , and σ (w_{0})=0.077 and σ (w_{a})=0.295 in the CPL model, which are comparable with the results of P l a n c k +BAO +SNe . In the Λ CDM model, the constraint precision of H_{0} and Ω_{m} is less than or rather close to 1%, indicating that the magnificent prospects for precision cosmology with these two promising cosmological probes are worth expecting.
 Publication:

Physical Review D
 Pub Date:
 November 2021
 DOI:
 10.1103/PhysRevD.104.103507
 arXiv:
 arXiv:2106.01859
 Bibcode:
 2021PhRvD.104j3507J
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 12 pages, 7 figures