Constraining $Λ$CDM cosmological parameters with Einstein Telescope mock data

Abstract

We investigate the capability of Einstein Telescope to constrain the cosmological parameters of the non-flat ΛCDM cosmological model. Two types of mock datasets are considered depending on whether or not a short Gamma-Ray Burst is detected and associated with the gravitational wave event using the THESEUS satellite. Depending on the mock dataset, different statistical estimators are applied: one assumes that the redshift is known, and another one marginalizes over it assuming a specific prior distribution. We demonstrate that (i) using mock catalogs collecting gravitational wave events to which a short Gamma-Ray Burst has been associated, Einstein Telescope may achieve an accuracy on the cosmological parameters of σ H 0 ≈ 0.40 km s −1 Mpc −1 , σ Ω k,0 ≈ 0.09, and σ Ω Λ,0 ≈ 0.07; while (ii) using mock catalogs collecting also gravitational wave events without a detected electromagnetic counterpart, Einstein Telescope may achieve an accuracy on the cosmological parameters of σ H 0 ≈ 0.04 km s −1 Mpc −1 , σ Ω k,0 ≈ 0.01, and σ Ω Λ,0 ≈ 0.01. These results show an improvement of a factor 2-75 with respect to earlier results using complementary datasets.

Uncertainty and bias of cosmology and astrophysical population model from statistical dark sirens

“…However, such bright sirens are rare and GW170817 is the only joint observation to date. Even with 3G detectors, Califano et al (2022) estimates that only 0.1% of detectable BNSs will have observable EM counterparts. Besides a direct EM counterpart, it is also possible to constrain cosmology from matter effects in coalescing BNSs (Messenger & Read 2012).…”