Cosmological constraints from low redshift 21 cm intensity mapping with machine learning

Sep 14, 2023
17 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 528 (2024) 2, 2078-2094
  • Published: 2023
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DOI:

Citations per year

20222023202402
Abstract: (arXiv)
The future 21 cm intensity mapping observations constitute a promising way to trace the matter distribution of the Universe and probe cosmology. Here we assess its capability for cosmological constraints using as a case study the BINGO radio telescope, that will survey the Universe at low redshifts (0.13<z<0.450.13 < z < 0.45). We use neural networks (NNs) to map summary statistics, namely, the angular power spectrum (APS) and the Minkowski functionals (MFs), calculated from simulations into cosmological parameters. Our simulations span a wide grid of cosmologies, sampled under the Λ\LambdaCDM scenario, {Ωc,h\Omega_c, h}, and under an extension assuming the Chevallier-Polarski-Linder (CPL) parameterization, {Ωc,h,w0,wa\Omega_c, h, w_0, w_a}. In general, NNs trained over APS outperform those using MFs, while their combination provides 27% (5%) tighter error ellipse in the Ωch\Omega_c-h plane under the Λ\LambdaCDM scenario (CPL parameterization) compared to the individual use of the APS. Their combination allows predicting Ωc\Omega_c and hh with 4.9% and 1.6% fractional errors, respectively, which increases to 6.4% and 3.7% under CPL parameterization. Although we find large bias on waw_a estimates, we still predict w0w_0 with 24.3% error. We also confirm our results to be robust to foreground contamination, besides finding the instrumental noise to cause the greater impact on the predictions. Still, our results illustrate the capability of future low redshift 21 cm observations in providing competitive cosmological constraints using NNs, showing the ease of combining different summary statistics.
Note:
  • 17 pages, 13 figures
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