TY - JOUR

T1 - Constraining the epoch of reionization with the variance statistic: simulations of the LOFAR case

AU - Patil, Ajinkya H.

AU - Zaroubi, Saleem

AU - Chapman, Emma

AU - Jelic, Vibor

AU - Harker, Geraint

AU - Abdalla, Filipe B.

AU - Asad, Khan M. B.

AU - Bernardi, Gianni

AU - Brentjens, Michiel A.

AU - de Bruyn, A. G.

AU - Bus, Sander

AU - Ciardi, Benedetta

AU - Daiboo, Soobash

AU - Fernandez, Elizabeth R.

AU - Ghosh, Abhik

AU - Jensen, Hannes

AU - Kazemi, Sanaz

AU - Koopmans, Léon V. E.

AU - Labropoulos, Panagiotis

AU - Mevius, Maaijke

AU - Martinez, Oscar

AU - Mellema, Garrelt

AU - Offringa, Andre R.

AU - Pandey, Vishambhar N.

AU - Schaye, Joop

AU - Thomas, Rajat M.

AU - Vedantham, Harish K.

AU - Veligatla, Vamsikrishna

AU - Wijnholds, Stefan J.

AU - Yatawatta, Sarod

PY - 2014/9/1

Y1 - 2014/9/1

N2 - 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.

AB - 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.

KW - methods: statistical

KW - techniques: interferometric

KW - dark ages

KW - reionization

KW - first stars

UR - http://adsabs.harvard.edu/abs/2014MNRAS.443.1113P

U2 - 10.1093/mnras/stu1178

DO - 10.1093/mnras/stu1178

M3 - Article

VL - 443

SP - 1113

EP - 1124

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -