Interferometric HI intensity mapping: perturbation theory predictions and foreground removal effects

Abstract

We provide perturbation theory predictions for the HI intensity mapping power spectrum multipoles using the Effective Field Theory of Large Scale Structure (EFTofLSS), which should allow us to constrain cosmological parameters exploiting mildly nonlinear scales. Assuming survey specifications typical of proposed interferometric HI intensity mapping experiments like CHORD and PUMA, and realistic ranges of validity for the perturbation theory modelling, we run mock full shape MCMC analyses at a redshift bin centred at $z=0.5$, and compare with Stage-IV optical galaxy surveys. We include the impact of 21cm foreground removal using simulations-based prescriptions, and quantify the effects on the precision and accuracy of the parameter estimation. We vary 11 parameters in total: 3 cosmological parameters, 7 bias and counterterms parameters, and the HI brightness temperature. Amongst them, the 4 parameters of interest are: the cold dark matter density, ${\omega }_{\mathrm{c}}$, the Hubble parameter, $h$, the primordial amplitude of the power spectrum, $A_{\mathrm{s}}$, and the linear HI bias, $b_1$. For the best case scenario, we obtain unbiased constraints on all parameters with $<3\%$ errors at $68\%$ confidence level. When we include the foreground removal effects, the parameter estimation becomes strongly biased for ${\omega }_{\mathrm{c}},h$, and $b_1$, while $A_{\mathrm{s}}$ is less biased ($<2\sigma$). We find that scale cuts $k_{\min }\ge 0.03h/\mathrm{Mpc}$ are required to return accurate estimates for ${\omega }_{\mathrm{c}}$ and $h$, at the price of a decrease in the precision, while $b_1$ remains strongly biased. We comment on the implications of these results for real data analyses.

11 pages, 1 table, 10 figures; matches version accepted for publication in MNRAS

References in corpus (13)

• Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy
• Measurement of 21 cm brightness fluctuations at z ~ 0.8 in cross-correlation
• Late-time cosmology with 21cm intensity mapping experiments
• A Method for 21cm Power Spectrum Estimation in the Presence of Foregrounds
• The Neutral Hydrogen Cosmological Mass Density at z=5
• Blind foreground subtraction for intensity mapping experiments
• HI intensity mapping with MeerKAT: power spectrum detection in cross-correlation with WiggleZ galaxies
• MultiDark-Galaxies: data release and first results
• SKAO HI Intensity Mapping: Blind Foreground Subtraction Challenge
• Measuring the growth of structure with intensity mapping surveys
• Cosmological constraints from the power spectrum and bispectrum of 21cm intensity maps
• An Effective Bias Expansion for 21 cm Cosmology in Redshift Space
• Redshift space distortions of the {\rm HI} 21-cm intensity mapping signal due to the internal motions within galaxies

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• Detecting the HI Power Spectrum in the Post-Reionization Universe with SKA-Low
• Multipole expansion for 21cm Intensity Mapping power spectrum: forecasted cosmological parameters estimation for the SKA Observatory
• Cosmological constraints from the EFT power spectrum and tree-level bispectrum of 21cm intensity maps
• Power spectrum multipoles and clustering wedges during the Epoch of Reionization