Forecasts on interacting dark energy from the 21-cm angular power spectrum with BINGO and SKA observations

Mar 2, 2021
20 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 510 (2021) 1, 1495-1514
  • Published: Dec 27, 2021
e-Print:

Citations per year

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Abstract: (Oxford University Press)
Neutral hydrogen (H i) intensity mapping is a promising technique to probe the large-scale structure of the Universe, improving our understanding of the late-time accelerated expansion. In this work, we first scrutinize how an alternative cosmology, interacting dark energy (IDE), can affect the 21-cm angular power spectrum relative to the concordance ΛCDM model. We re-derive the 21-cm brightness temperature fluctuation in the context of such an interaction and uncover an extra new contribution. Then we estimate the noise level of three upcoming H i intensity mapping surveys, namely Baryon Acoustic Oscillations from Integrated Neutral Gas Observations (BINGO), Square Kilometre Array (SKA1)-MID Band 1 and Band 2, and employ a Fisher matrix approach to forecast their constraints on the IDE model. We find that while Planck 2018 maintains its dominion over early-Universe parameter constraints, BINGO and SKA1-MID Band 2 provide complementary bounding to the latest cosmic microwave background measurements on the dark energy equation of state w, the interacting strength λ_i and the reduced Hubble constant h, and that SKA1-MID Band 1 even outperforms Planck 2018 in these late-Universe parameter constraints. The expected minimum uncertainties are given by SKA1-MID Band 1 + Planck: |0.34 per cent\sim 0.34{{\ \rm per\ cent}}| on w, |0.22 per cent\sim 0.22{{\ \rm per\ cent}}| on h, |0.64 per cent\sim 0.64{{\ \rm per\ cent}}| on H i bias b_H_i, and an absolute uncertainty of about 3 × 10^−4 (7 × 10^−4) on λ_1 (λ_2). Moreover, we quantify the effects from systematics of the redshift bin number, redshift-space distortions, foreground residuals and uncertainties on the measured H i fraction, Ω_H_i(z). Our results indicate a bright prospect for H i intensity mapping surveys in constraining IDE, whether on their own or by synergies with other measurements.
Note:
  • 20 pages, 13 figures, 9 tables, accepted for publication in MNRAS
  • instrumentation: spectrographs
  • methods: analytical
  • cosmological parameters
  • dark energy: interaction
  • power spectrum: angular dependence
  • dark energy: equation of state
  • temperature: fluctuation
  • expansion: acceleration
  • satellite: Planck
  • cosmological model