Naslov
Constraining the epoch of reionization with the variance statistic: simulations of the LOFAR case

Autori
Patil, Ajinkya H. ; Zaroubi, Saleem ; Chapman, Emma ; Jelić, Vibor ; Harker, Geraint ; Abdalla, Filipe B. ; Asad, Khan M.B. ; Bernardi, Gianni ; Brentjens, Michiel A. ; de Bruyn, A.G. ; Bus, Sander ; Ciardi, Benedetta ; Daiboo, Soobash ; Fernandez, Elizabeth R. ; Ghosh, Abhik ; Jensen, Hannes ; Kazemi, Sanaz ; Koopmans, Léon V.E. ; Labropoulos, Panagiotis ; Mevius, Maaijke ; Martinez, Oscar ; Mellema, Garrelt ; Offringa, Andre R. ; Pandey, Vishhambhar N. ; Schaye, Joop ; Thomas, Rajat M. ; Vedantham, Harish K. ; Veligatla, Vamsikrishna ; Wijnholds, Stefan J. ; Yatawatta, Sarod

Izvornik
Monthly notices of the Royal Astronomical Society (0035-8711) 443 (2014), 2; 1113-1124

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
methods: statistical; techniques: interferometric; dark ages; reionization; first stars

Sažetak
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 (zr) and duration (Δz) of reionization can be constrained assuming a parametrization. We use an EoR simulation of zr = 7.68 and Δz = 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^{; ; +0.37}; ; _{; ; -0.18}; ; and Δ z = 0.53^{; ; +0.12}; ; _{; ; -0.23}; ; 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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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