Quantifying the non-Gaussianity in the EoR 21-cm signal through bispectrum

Abstract

The epoch of reionization (EoR) 21-cm signal is expected to be highly non-Gaussian in nature and this non-Gaussianity is also expected to evolve with the progressing state of reionization. Therefore the signal will be correlated between different Fourier modes ($k$). The power spectrum will not be able capture this correlation in the signal. We use a higher-order estimator -- the bispectrum -- to quantify this evolving non-Gaussianity. We study the bispectrum using an ensemble of simulated 21-cm signal and with a large variety of $k$ triangles. We observe two competing sources driving the non-Gaussianity in the signal: fluctuations in the neutral fraction ($x_{\mathrm{HI}}$) field and fluctuations in the matter density field. We find that the non-Gaussian contribution from these two sources vary, depending on the stage of reionization and on which $k$ modes are being studied. We show that the sign of the bispectrum works as a unique marker to identify which among these two components is driving the non-Gaussianity. We propose that the sign change in the bispectrum, when plotted as a function of triangle configuration $\cos \theta$ and at a certain stage of the EoR can be used as a confirmative test for the detection of the 21-cm signal. We also propose a new consolidated way to visualize the signal evolution (with evolving ${\overline{x}}_{\mathrm{HI}}$ or redshift), through the trajectories of the signal in a power spectrum and equilateral bispectrum i.e. $P(k)-B(k,k,k)$ space.

18 pages, 11 figures. Accepted for publication in MNRAS. Replaced to match the accepted version

References in corpus (36)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• Observational constraints on Cosmic Reionization
• Efficient Simulations of Early Structure Formation and Reionization
• Evidence of patchy hydrogen reionization from an extreme Ly$\alpha$ trough below redshift six
• The morphology of HII regions during reionization
• Upper limits on the 21-cm Epoch of Reionization power spectrum from one night with LOFAR
• 21 cm fluctuations from inhomogeneous X-ray heating before reionization
• Foreground simulations for the LOFAR - Epoch of Reionization Experiment
• 21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal
• The CMBR fluctuations from HI perturbations prior to reionization
• Evolution of the 21 cm signal throughout cosmic history
• Inside-out or Outside-in: The topology of reionization in the photon-starved regime suggested by Lyman-alpha forest data
• Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array
• On using visibility correlations to probe the HI distribution from the dark ages to the present epoch I: Formalism and the expected signal
• First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7
• Lyman-alpha emitters gone missing: evidence for late reionization?
• Foregrounds for redshifted 21 cm studies of reionization: GMRT 153 MHz observations
• 21 cm signal from cosmic dawn: Imprints of spin temperature fluctuations and peculiar velocities
• The multi-frequency angular power spectrum of the epoch of reionization 21 cm signal
• Characterizing Foreground for redshifted 21-cm radiation: 150 MHz GMRT observations
• Emulation of reionization simulations for Bayesian inference of astrophysics parameters using neural networks
• The Scattering of Lyman-series Photons in the Intergalactic Medium
• Initial LOFAR observations of Epoch of Reionization windows: II. Diffuse polarized emission in the ELAIS-N1 field
• A New Constraint on Reionization from Evolution of the Ly$\alpha$ Luminosity Function at $z\sim 6-7$ Probed by a Deep Census of $z=7.0$ Ly$\alpha$ Emitter Candidates to 0.3 $L^{\ast }$
• The rich complexity of 21-cm fluctuations produced by the first stars
• Higher Order Contributions to the 21 cm Power Spectrum
• The effect of non-Gaussianity on error predictions for the Epoch of Reionization (EoR) 21-cm power spectrum
• Detection and extraction of signals from the epoch of reionization using higher order one-point statistics
• A fast estimator for the bispectrum and beyond - A practical method for measuring non-Gaussianity in 21-cm maps
• Towards simulating and quantifying the light-cone EoR 21-cm signal
• Observations of the Lyman series forest towards the redshift 7.1 quasar ULAS J1120+0641
• Sensitivity for 21cm Bispectrum from Epoch of Reionization
• Implications of WMAP 3 Year Data for the Sources of Reionization
• Studying 21cm power spectrum with one-point statistics
• Reconstructing the nature of the first cosmic sources from the anisotropic 21-cm signal

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• Detection of Cosmic Structures using the Bispectrum Phase. II. First Results from Application to Cosmic Reionization Using the Hydrogen Epoch of Reionization Array
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• Detectability of 21cm-signal during the Epoch of Reionization with 21cm-Lyman-α emitter cross-correlation. II. Foreground contamination
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• On the general nature of 21cm-Lyman-$\alpha$ emitters cross-correlations during reionisation
• Redshifted 21-cm bispectrum: Impact of the source models on the signal and the IGM physics from the Cosmic Dawn
• Suppressing variance in 21-cm signal simulations during reionization
• SKA-Low Intensity Mapping Pathfinder Updates: Deeper 21 cm Power Spectrum Limits from Improved Analysis Frameworks
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• PINION: Physics-informed neural network for accelerating radiative transfer simulations for cosmic reionization
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• Robust statistics toward detection of the 21 cm signal from the Epoch of Reionisation
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• Leveraging cross-correlations and linear covariance-based filtering for line-intensity map reconstructions at linear scales
• Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-Point Statistics
• MCMC generation of cosmological fields far beyond Gaussianity
• From ANN to BNN: Inferring Reionization Parameters using Uncertainty-aware Emulators of 21-cm Summaries
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• Interpreting the HI 21-cm cosmology maps through Largest Cluster Statistics. Part II. Impact of the realistic foreground and instrumental noise on synthetic SKA1-Low observations
• Classification of Radio Backgrounds at Cosmic Dawn and 21 cm Signal Confirmation Using Neural Networks
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