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Constraining the epoch of reionization with the variance statistic: simulations of the LOFAR case
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2014 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 443, no 2, 1113-1124 p.Article in journal (Refereed) Published
Abstract [en]

Several experiments are underway to detect the cosmic-redshifted 21-cm signal from neutral hydrogen from the Epoch of Reionization (EoR). Due to their very low signal-to-noise ratio, these observations aim for a statistical detection of the signal by measuring its power spectrum. We investigate the extraction of the variance of the signal as a first step towards detecting and constraining the global history of the EoR. Signal variance is the integral of the signal's power spectrum, and it is expected to be measured with a high significance. We demonstrate this through results from a simulation and parameter estimation pipeline developed for the Low-Frequency Array (LOFAR)-EoR experiment. We show that LOFAR should be able to detect the EoR in 600 h of integration using the variance statistic. Additionally, the redshift (z(r)) and duration (Delta z) of reionization can be constrained assuming a parametrization. We use an EoR simulation of z(r) = 7.68 and Delta(z) = 0.43 to test the pipeline. We are able to detect the simulated signal with a significance of four standard deviations and extract the EoR parameters as z(r) = 7.72(-0.18)(+0.37) and Delta z = 0.53(-0.23)(+0.12) in 600 h, assuming that systematic errors can be adequately controlled. We further show that the significance of detection and constraints on EoR parameters can be improved by measuring the cross-variance of the signal by cross-correlating consecutive redshift bins.

Place, publisher, year, edition, pages
2014. Vol. 443, no 2, 1113-1124 p.
Keyword [en]
methods: statistical, techniques: interferometric, dark ages, reionization, first stars
National Category
Astronomy, Astrophysics and Cosmology
Research subject
URN: urn:nbn:se:su:diva-107412DOI: 10.1093/mnras/stu1178ISI: 000340436800013OAI: diva2:748713


Available from: 2014-09-21 Created: 2014-09-15 Last updated: 2015-03-30Bibliographically approved

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Jensen, HannesMellema, Garrelt
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Department of AstronomyThe Oskar Klein Centre for Cosmo Particle Physics (OKC)
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Monthly notices of the Royal Astronomical Society
Astronomy, Astrophysics and Cosmology

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