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

Koki Kakiichi, Suman Majumdar, Garrelt Mellema, Benedetta Ciardi, Keri L. Dixon, Ilian T. Iliev, Vibor Jelić, Léon V. E. Koopmans, Saleem Zaroubi, Philipp Busch

OnderzoeksoutputAcademicpeer review

30 Citaten (Scopus)
212 Downloads (Pure)


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.
Originele taal-2English
Pagina's (van-tot)1936-1954
Aantal pagina's19
TijdschriftMonthly Notices of the Royal Astronomical Society
Nummer van het tijdschrift2
StatusPublished - okt.-2017

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