Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator -- IV. Wideband analysis

Abstract

We present a Wideband Tapered Gridded Estimator (TGE), which incorporates baseline migration and variation of the primary beam pattern for neutral hydrogen ($\mathrm{H}\mathrm{I}$) 21-cm intensity mapping (IM) with large frequency bandwidth radio-interferometric observations. Here we have analysed $394-494\mathrm{MHz}$ $(z=1.9-2.6)$ uGMRT data to estimate the Multi-frequency Angular Power Spectrum (MAPS) $C_{\ell }(\Delta \nu )$ from which we have removed the foregrounds using the polynomial fitting (PF) and Gaussian Process Regression (GPR) methods developed in our earlier work. Using the residual $C_{\ell }(\Delta \nu )$ to estimate the mean squared 21-cm brightness temperature fluctuation ${\Delta }^2(k)$, we find that this is consistent with $0\pm 2\sigma$ in several $k$ bins. The resulting $2\sigma$ upper limit ${\Delta }^2(k)<(4.68{)}^2\mathrm{m}{\mathrm{K}}^2$ at $k=0.219\mathrm{Mp}{\mathrm{c}}^{-1}$ is nearly $15$ times tighter than earlier limits obtained from a smaller bandwidth ($24.4\mathrm{MHz}$) of the same data. The $2\sigma$ upper limit $[{\Omega }_{\mathrm{H}\mathrm{I}}{b}_{\mathrm{H}\mathrm{I}}]<1.01\times 10^{-2}$ is within an order of magnitude of the value expected from independent estimates of the $\mathrm{H}\mathrm{I}$ mass density ${\Omega }_{\mathrm{H}\mathrm{I}}$ and the $\mathrm{H}\mathrm{I}$ bias $b_{\mathrm{H}\mathrm{I}}$. The techniques used here can be applied to other telescopes and frequencies, including $\sim 150\mathrm{MHz}$ Epoch of Reionization observations.

Accepted for publication in MNRAS

References in corpus (24)

• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Baryon acoustic oscillations with Lyman-$\alpha$ forests
• Measurement of 21 cm brightness fluctuations at z ~ 0.8 in cross-correlation
• 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
• Deep multi-redshift limits on Epoch of Reionisation 21cm Power Spectra from Four Seasons of Murchison Widefield Array Observations
• On using visibility correlations to probe the HI distribution from the dark ages to the present epoch I: Formalism and the expected signal
• The 1.28 GHz MeerKAT DEEP2 Image
• The multi-frequency angular power spectrum of the epoch of reionization 21 cm signal
• HI intensity mapping with MeerKAT: power spectrum detection in cross-correlation with WiggleZ galaxies
• Neutral hydrogen (HI) gas content of galaxies at $z\approx 0.32$
• First Detection of Cosmic Structure in the 21-cm Intensity Field
• Visibility based angular power spectrum estimation in low frequency radio interferometric observations
• Statistical properties of damped Lyman-alpha systems from Sloan Digital Sky Survey DR12
• GMRT observation towards detecting the Post-reionization 21-cm signal
• A direct detection of neutral hydrogen intensity mapping on Mpc scales at $z\approx 0.32$ and $z\approx 0.44$
• A Tapered Gridded Estimator (TGE) for the Multi-Frequency Angular Power Spectrum (MAPS) and the Cosmological HI 21-cm Power Spectrum
• First multi-redshift limits on post-Epoch of Reionization (post-EoR) 21 cm signal from z = 1.96 - 3.58 using uGMRT
• Extracting the 21 cm EoR signal using MWA drift scan data
• Statistical recovery of 21cm visibilities and their power spectra with Gaussian constrained realisations and Gibbs sampling
• Statistical analysis of the causes of excess variance in the 21 cm signal power spectra obtained with the Low-Frequency Array
• Towards 21-cm Intensity Mapping at $z=2.28$ with uGMRT using the Tapered Gridded Estimator I: Foreground Avoidance
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator III: Foreground removal
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator II: Cross-polarization power spectrum
• A Detection of Cosmological 21 cm Emission from CHIME in Cross-correlation with eBOSS Measurements of the Lyman-$\alpha$ Forest

Cited by in corpus (4)

• The Tracking Tapered Gridded Estimator for the 21-cm power spectrum from MWA drift scan observations I: Validation and preliminary results
• Needlets and foreground removal for SKAO hydrogen intensity maps
• HI Intensity Mapping cross-correlation with thermal SZ fluctuations: forecasted cosmological parameters estimation for FAST and Planck
• Bayes-SCF: A Bayesian filter to mitigate foreground leakage in the 21-cm power spectrum