Theoretical uncertainties on non-linear scales are among the main obstacles to exploit the sensitivity of forthcoming galaxy and hydrogen surveys like Euclid or the Square Kilometre Array (SKA). Here, we devise a new method to model the theoretical error that goes beyond the usual cut-off on small scales. The advantage of this more efficient implementation of the non-linear uncertainties is tested through a Markov-Chain-Monte-Carlo (MCMC) forecast of the sensitivity of Euclid and SKA to the parameters of the standard ΛCDM model, including massive neutrinos with total mass Mν, and to 3 extended scenarios, including 1) additional relativistic degrees of freedom (ΛCDM + Mν + Neff), 2) a deviation from the cosmological constant (ΛCDM + Mν + w0), and 3) a time-varying dark energy equation of state parameter (ΛCDM + Mν + (w0,wa )). We compare the sensitivity of 14 different combinations of cosmological probes and experimental configurations. For Euclid combined with Planck, assuming a plain cosmological constant, our method gives robust predictions for a high sensitivity to the primordial spectral index ns (σ(ns)=0.00085), the Hubble constant H0 (σ(H0)=0.141 km/s/Mpc), the total neutrino mass Mν (σ(Mν)=0.020 eV). Assuming dynamical dark energy we get σ(Mν)=0.030 eV for the mass and (σ(w0), σ(wa)) = (0.0214, 0.071) for the equation of state parameters. The predicted sensitivity to Mν is mostly stable against the extensions of the cosmological model considered here. Interestingly, a significant improvement of the constraints on the extended model parameters is also obtained when combining Euclid with a low redshift HI intensity mapping survey by SKA1, demonstrating the importance of the synergy of Euclid and SKA.

Cosmology in the era of Euclid and the Square Kilometre Array

Thejs Brinckmann;
2019

Abstract

Theoretical uncertainties on non-linear scales are among the main obstacles to exploit the sensitivity of forthcoming galaxy and hydrogen surveys like Euclid or the Square Kilometre Array (SKA). Here, we devise a new method to model the theoretical error that goes beyond the usual cut-off on small scales. The advantage of this more efficient implementation of the non-linear uncertainties is tested through a Markov-Chain-Monte-Carlo (MCMC) forecast of the sensitivity of Euclid and SKA to the parameters of the standard ΛCDM model, including massive neutrinos with total mass Mν, and to 3 extended scenarios, including 1) additional relativistic degrees of freedom (ΛCDM + Mν + Neff), 2) a deviation from the cosmological constant (ΛCDM + Mν + w0), and 3) a time-varying dark energy equation of state parameter (ΛCDM + Mν + (w0,wa )). We compare the sensitivity of 14 different combinations of cosmological probes and experimental configurations. For Euclid combined with Planck, assuming a plain cosmological constant, our method gives robust predictions for a high sensitivity to the primordial spectral index ns (σ(ns)=0.00085), the Hubble constant H0 (σ(H0)=0.141 km/s/Mpc), the total neutrino mass Mν (σ(Mν)=0.020 eV). Assuming dynamical dark energy we get σ(Mν)=0.030 eV for the mass and (σ(w0), σ(wa)) = (0.0214, 0.071) for the equation of state parameters. The predicted sensitivity to Mν is mostly stable against the extensions of the cosmological model considered here. Interestingly, a significant improvement of the constraints on the extended model parameters is also obtained when combining Euclid with a low redshift HI intensity mapping survey by SKA1, demonstrating the importance of the synergy of Euclid and SKA.
2019
Sprenger, Tim; Archidiacono, Maria; Brinckmann, Thejs Ehlert; Clesse, Sébastien; Lesgourgues, Julien
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2503098
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