Studying the morphology of reionisation with the triangle correlation function of phases
File(s)
Accepted version
Author(s)
Gorce, Adélie
Pritchard, Jonathan R
Type
Journal Article
Abstract
Abstract
We present a new statistical tool, called the triangle correlation function (TCF), inspired by the earlier work of Obreschkow et al. (2013). It is derived from the 3-point correlation function and aims to probe the characteristic scale of ionised regions during the Epoch of Reionisation from 21cm interferometric observations. Unlike most works, which focus on power spectrum, i.e. amplitude information, our statistic is based on the information we can extract from the phases of the Fourier transform of the ionisation field. In this perspective, it may benefit from the well-known interferometric concept of closure phases. We find that this statistical estimator performs very well on simple ionisation fields. For example, with well-defined fully ionised disks, there is a peaking scale, which we can relate to the radius of the ionised bubbles. We also explore the robustness of the TCF when observational effects such as angular resolution and noise are considered. We also get interesting results on fields generated by more elaborate simulations such as 21CMFAST. Although the variety of sources and ionised morphologies in the early stages of the process make its interpretation more challenging, the nature of the signal can tell us about the stage of reionisation. Finally, and in contrast to other bubble size distribution algorithms, we show that the TCF can resolve two different characteristic scales in a given map.
We present a new statistical tool, called the triangle correlation function (TCF), inspired by the earlier work of Obreschkow et al. (2013). It is derived from the 3-point correlation function and aims to probe the characteristic scale of ionised regions during the Epoch of Reionisation from 21cm interferometric observations. Unlike most works, which focus on power spectrum, i.e. amplitude information, our statistic is based on the information we can extract from the phases of the Fourier transform of the ionisation field. In this perspective, it may benefit from the well-known interferometric concept of closure phases. We find that this statistical estimator performs very well on simple ionisation fields. For example, with well-defined fully ionised disks, there is a peaking scale, which we can relate to the radius of the ionised bubbles. We also explore the robustness of the TCF when observational effects such as angular resolution and noise are considered. We also get interesting results on fields generated by more elaborate simulations such as 21CMFAST. Although the variety of sources and ionised morphologies in the early stages of the process make its interpretation more challenging, the nature of the signal can tell us about the stage of reionisation. Finally, and in contrast to other bubble size distribution algorithms, we show that the TCF can resolve two different characteristic scales in a given map.
Date Issued
2019-10-01
Date Acceptance
2019-07-29
Citation
Monthly Notices of the Royal Astronomical Society, 2019, 489 (1), pp.1321-1337
ISSN
0035-8711
Publisher
Oxford University Press (OUP)
Start Page
1321
End Page
1337
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
489
Issue
1
Copyright Statement
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
Sponsor
Commission of the European Communities
Identifier
https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stz2195/5545599
Grant Number
638743
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
methods: statistical
dark ages, reionization, first stars
large-scale structure of Universe
cosmology: theory
SIZE STATISTICS
NON-GAUSSIANITY
HII-REGIONS
21-CM
BISPECTRUM
EPOCH
SIMULATIONS
COSMOLOGY
TOPOLOGY
GROWTH
astro-ph.CO
astro-ph.CO
astro-ph.IM
Astronomy & Astrophysics
0201 Astronomical and Space Sciences
Publication Status
Published online
Date Publish Online
2019-08-09