Recovering the HII region size statistics from 21-cm tomography

Abstract

We introduce a novel technique, called "granulometry", to characterize and recover the mean size and the size distribution of HII regions from 21-cm tomography. The technique is easy to implement, but places the previously not very well defined concept of morphology on a firm mathematical foundation. The size distribution of the cold spots in 21-cm tomography can be used as a direct tracer of the underlying probability distribution of HII region sizes. We explore the capability of the method using large-scale reionization simulations and mock observational data cubes while considering capabilities of SKA1-low and a future extension to SKA2. We show that the technique allows the recovery of the HII region size distribution with a moderate signal-to-noise ratio from wide-field imaging ($\mathrm{SNR}\lesssim 3$), for which the statistical uncertainty is sample variance dominated. We address the observational requirements on the angular resolution, the field-of-view, and the thermal noise limit for a successful measurement. To achieve a full scientific return from 21-cm tomography and to exploit a synergy with 21-cm power spectra, we suggest an observing strategy using wide-field imaging (several tens of square degrees) by an interferometric mosaicking/multi-beam observation with additional intermediate baselines (~2-4 km).

19 pages, 19 figures, the version accepted in MNRAS

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Cited by in corpus (38)

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• Optimal identification of HII regions during reionization in 21-cm observations
• The 21cm bispectrum as a probe of non-Gaussianities due to X-ray heating
• The 21cm bispectrum during reionization: a tracer of the ionization topology
• A fast estimator for the bispectrum and beyond - A practical method for measuring non-Gaussianity in 21-cm maps
• Measuring the topology of reionization with Betti numbers
• Fuzzy Dark Matter at Cosmic Dawn: New 21-cm Constraints
• Deep learning approach for identification of HII regions during reionization in 21-cm observations
• Exploring the cosmic 21-cm signal from the Epoch of Reionisation using the Wavelet Scattering Transform
• The Shape and Size distribution of HII Regions near the percolation transition
• Prospects of constraining reionization model parameters using Minkowski tensors and Betti numbers
• Persistent topology of the reionisation bubble network. I: Formalism & Phenomenology
• Inferring the properties of the sources of reionization using the morphological spectra of the ionized regions
• The THESAN project: connecting ionized bubble sizes to their local environments during the Epoch of Reionization
• Studying the morphology of reionisation with the triangle correlation function of phases
• Reionisation & Cosmic Dawn Astrophysics from the Square Kilometre Array: Impact of Observing Strategies
• Detecting the non-Gaussianity of the 21-cm signal during reionisation with the Wavelet Scattering Transform
• Probing early universe through redshifted 21-cm signal: Modelling and observational challenges
• Detectability of 21cm-signal during the Epoch of Reionization with 21cm-Lyman-α emitter cross-correlation. II. Foreground contamination
• Persistent topology of the reionization bubble network. II: Evolution & Classification
• SKA-Low Intensity Mapping Pathfinder Updates: Deeper 21 cm Power Spectrum Limits from Improved Analysis Frameworks
• A galaxy-free phenomenological model for the 21-cm power spectrum during reionization
• Opening Reionization: Quantitative Morphology of the Epoch of Reionization and Its Connection to the Cosmic Density Field
• Estimation of HII Bubble Size Distribution from 21cm Power Spectrum with Artificial Neural Networks
• Distinguishing reionization models using the largest cluster statistics of the 21-cm maps
• Probing quasar lifetimes with proximate $21$-centimetre absorption in the diffuse intergalactic medium at redshifts $z\ge 6$
• Using the sample variance of 21cm maps as a tracer of the ionisation topology
• Analysing the Epoch of Reionization with three-point correlation functions and machine learning techniques
• Modeling Post-Reionization HI Distributions in Fuzzy Dark Matter Cosmologies Using Conditional Normalizing Flows
• Interpreting the HI 21-cm cosmology maps through Largest Cluster Statistics -- I: Impact of the synthetic SKA1-Low observations
• Topology of Reionisation times: concepts, measurements and comparisons to gaussian random field predictions
• The variance of dispersion measure of high-redshift transient objects as a probe of ionized bubble size during reionization
• Effects of Small-Scale Absorption Systems on Neutral Islands during the Late Epoch of Reionization
• Reionization Parameter Inference from 3D Minkowski Functionals of the 21 cm Signals
• Mapping neutral islands during end stages of reionization with photometric intergalactic medium tomography
• 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