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

Kakiichi, Koki, Majumdar, Suman, Mellema, Garrelt, Ciardi, Benedetta, Dixon, Keri L, Iliev, Ilian T, Jelić, Vibor, Koopmans, Léon V E, Zaroubi, Saleem and Busch, Philipp (2017) Recovering the H II region size statistics from 21-cm tomography. Monthly Notices of the Royal Astronomical Society, 471 (2). pp. 1936-1954. ISSN 0035-8711

[img] PDF (This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.) - Published Version
Available under License All Rights Reserved.

Download (6MB)


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 SquareKilometreArray 1 (SKA1) lowand 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 (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 widefield imaging (several tens of square degrees) by an interferometric mosaicking/multibeam observation with additional intermediate baselines (∼2−4 km) in an SKA phase 2.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QB Astronomy
Depositing User: Billy Wichaidit
Date Deposited: 06 Jun 2018 15:00
Last Modified: 07 Jun 2018 10:58

View download statistics for this item

📧 Request an update
Project NameSussex Project NumberFunderFunder Ref