Abstract
Using the 21 cm intensity mapping (IM) technique can efficiently perform
large-scale neutral hydrogen (HI) survey, and thus can detect the baryon
acoustic oscillation (BAO) signals in the large-scale HI distribution. This
method has great potential for measuring dark-energy parameters. Some 21 cm IM
experiments have been proposed and performed, of which the typical ones include
BINGO, FAST, SKA1, HIRAX, CHIME, and Tianlai. In this work, we make a forecast
for these typical 21 cm IM experiments in their capability of measuring
parameters of dark energy. We find that the interferometers have great
advantages in constraining cosmological parameters. In particular, the Tianlai
cylinder array alone can achieve the standard of precision cosmology for the
$Łambda$CDM model. However, for constraining dynamical dark energy, we find
that SKA1-MID performs very well (using its single-dish mode). In addition, we
show that the simulated 21 cm IM data can break the parameter degeneracies
inherent in the CMB data, and CMB+SKA1 offers $\sigma(w)=0.013$ in the $w$CDM
model, and $\sigma(w_0)=0.080$ and $\sigma(w_a)=0.25$ in the CPL model.
Compared with CMB+BAO+SN, Tianlai can provide tighter constraints in
$Łambda$CDM and $w$CDM, but looser constraints (tighter than CMB+BAO) in CPL,
and the combination CMB+BAO+SN+Tianlai gives $\sigma(w)=0.013$,
$\sigma(w_0)=0.055$, and $\sigma(w_a)=0.13$. Finally, we find that the residual
foreground contamination amplitude has a considerable impact on constraint
results. We show that in the future 21 cm IM experiments will provide a
powerful probe for exploring the nature of dark energy.
Description
Prospects for measuring dark energy with 21 cm intensity mapping experiments
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