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Recovering the H II region size statistics from 21-cm tomography

Kakiichi, K; Majumdar, S; Mellema, G; Ciardi, B; Dixon, KL; Iliev, IT; Jelic, V; ... Busch, P; + view all (2017) Recovering the H II region size statistics from 21-cm tomography. Monthly Notices of the Royal Astronomical Society , 471 (2) pp. 1936-1954. 10.1093/mnras/stx1568. Green open access

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We introduce a novel technique, called ‘granulometry’, to characterize and recover the mean size and the size distribution of H II 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 H II region sizes. We explore the capability of the method using large-scale reionization simulations and mock observational data cubes while considering capabilities of Square Kilometre Array 1 (SKA1) low and a future extension to SKA2. We show that the technique allows the recovery of the H II region size distribution with a moderate signal-to-noise ratio from wide-field imaging (SNR 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/multibeam observation with additional intermediate baselines (∼2−4 km) in an SKA phase 2.

Type: Article
Title: Recovering the H II region size statistics from 21-cm tomography
Open access status: An open access version is available from UCL Discovery
DOI: 10.1093/mnras/stx1568
Publisher version: http://doi.org/10.1093/mnras/stx1568
Language: English
Additional information: © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Science & Technology, Physical Sciences, Astronomy & Astrophysics, radiative transfer, methods: data analysis, techniques: image processing, intergalactic medium, dark ages, reionization, first stars, cosmology: theory, SIMULATING COSMIC REIONIZATION, DETECTING IONIZED BUBBLES, 21 CENTIMETER TOMOGRAPHY, POWER-SPECTRUM, LARGE SCALES, COSMOLOGICAL REIONIZATION, HYDROGEN REIONIZATION, INTERGALACTIC MEDIUM, NEUTRAL HYDROGEN, HIGH-REDSHIFT
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1559486
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