Detecting the HI Power Spectrum in the Post-Reionization Universe with SKA-Low

Abstract

We present a survey strategy to detect the neutral hydrogen (HI) power spectrum at $5<z<6$ using the SKA-Low radio telescope in presence of foregrounds and instrumental effects. We simulate observations of the inherently weak HI signal post-reionization with varying levels of noise and contamination with foreground amplitudes equivalent to residuals after sky model subtraction. We find that blind signal separation methods on imaged data are required in order to recover the HI signal at large cosmological scales. Comparing different methods of foreground cleaning, we find that Gaussian Process Regression (GPR) performs better than Principle Component Analysis (PCA), with the key difference being that GPR uses smooth kernels for the total data covariance. The integration time of one field needs to be larger than $\sim 250$ h to provide large enough signal-to-noise ratio (SNR) to accurately model the data covariance for foreground cleaning. Images within the primary beam field-of-view give measurements of the HI power spectrum at scales $k\sim 0.02\mathrm{Mp}{\mathrm{c}}^{-1}-0.3\mathrm{Mp}{\mathrm{c}}^{-1}$ with SNR $\sim 2-5$ in $\Delta [\log (k/\mathrm{Mp}{\mathrm{c}}^{-1})]=0.25$ bins assuming an integration time of $600$ h. Systematic effects, which introduce small-scale fluctuations across frequency channels, need to be $\lesssim 5\times 10^{-5}$ to enable unbiased measurements outside the foreground wedge. Our results provide an important validation towards using the SKA-Low array for measuring the HI power spectrum in the post-reionization Universe.

17 pages, 22 figures. Updated to match the published version in MNRAS

References in corpus (34)

• Array Programming with NumPy
• A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Dark Energy Survey Year 3 Results: Cosmology from Cosmic Shear and Robustness to Data Calibration
• Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy
• Measurement of 21 cm brightness fluctuations at z ~ 0.8 in cross-correlation
• The non-coplanar baselines effect in radio interferometry: The W-Projection algorithm
• Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at $\mathbf{z}\approx 9.1$ from LOFAR
• Post-correlation radio frequency interference classification methods
• Hydrogen reionisation ends by $z=5.3$: Lyman-$\alpha$ optical depth measured by the XQR-30 sample
• How accurately can 21 cm tomography constrain cosmology?
• The Epoch of Reionization Window: I. Mathematical Formalism
• Deep multi-redshift limits on Epoch of Reionisation 21cm Power Spectra from Four Seasons of Murchison Widefield Array Observations
• The Neutral Hydrogen Cosmological Mass Density at z=5
• First Season MWA EoR Power Spectrum Results at Redshift 7
• The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation
• Line-Intensity Mapping: 2017 Status Report
• The Scale of the Problem : Recovering Images of Reionization with GMCA
• HI intensity mapping with MeerKAT: power spectrum detection in cross-correlation with WiggleZ galaxies
• HI constraints from the cross-correlation of eBOSS galaxies and Green Bank Telescope intensity maps
• Detection of Cosmological 21 cm Emission with the Canadian Hydrogen Intensity Mapping Experiment
• Forecasts on the Dark Energy and Primordial Non-Gaussianity Observations with the Tianlai Cylinder Array
• SKAO HI Intensity Mapping: Blind Foreground Subtraction Challenge
• Comparing Foreground Removal Techniques for Recovery of the LOFAR-EoR 21cm Power Spectrum
• Foreground removal for Square Kilometre Array observations of the Epoch of Reionization with the Correlated Component Analysis
• Gaussian Process Regression for foreground removal in HI intensity mapping experiments
• MIGHTEE-HI: Evolution of HI scaling relations of star-forming galaxies at $z<0.5$
• MIGHTEE-HI: the HI Size-Mass relation over the last billion years
• Observing the Reionization : Effect of Calibration and Position Errors on Realistic Observation Conditions
• Interferometric HI intensity mapping: perturbation theory predictions and foreground removal effects
• Building models for extended radio sources: implications for Epoch of Reionisation science
• Contribution of Galactic free-free emission to the foreground for EoR signal in SKA experiments
• Towards Optimal Foreground Mitigation Strategies for Interferometric HI Intensity Mapping in the Low-Redshift Universe
• Impact of inhomogeneous reionization on post-reionization 21 cm intensity mapping measurement of cosmological parameters

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