A Study of Fundamental Limitations to Statistical Detection of Redshifted H I From the Epoch of Reionization

Thyagarajan, Nithyanandan; Shankar, N. Udaya; Subrahmanyan, R.; Arcus, W.; Bernardi, G.; Bowman, Judd D.; Briggs, F.; Bunton, John D.; Cappallo, R. J.; Corey, B. E.; deSouza, L.; Emrich, D.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Herne, D.; Hewitt, Jacqueline N.; Johnston‐Hollitt, M.; Kaplan, D. L.; Kasper, J. C.; Kincaid, B. B.; Koenig, R.; Kratzenberg, E.; Lonsdale, Colin J.; Lynch, M. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Pathikulangara, J.; Remillard, Ronald A.; Rogers, A. E. E.; Roshi, D. Anish; Salah, J. E.; Sault, R. J.; Srivani, K. S.; Stevens, J.; Prabu, T.; Tingay, S. J.; Wayth, R. B.; Waterson, M.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, Christopher; Wyithe, J. Stuart B.

doi:10.1088/0004-637x/776/1/6

Cited by 155 publications

(155 citation statements)

References 55 publications

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“…This relationship, known colloquially as "the wedge," was derived analytically (P12b; Vedantham et al 2012;Thyagarajan et al 2013;Liu et al 2014aLiu et al , 2014b, and has been confirmed in simulations (Datta et al 2010;Hazelton et al 2013) and observationally Dillon et al 2014). As described in P12b, the wedge is the result of the delay between when a wavefront originating from foreground emission arrives at the two antennas in a baseline.…”

Section: Calibrationmentioning

confidence: 70%

PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM ATz= 8.4

Ali

Parsons

Zheng

et al. 2015

ApJ

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In this paper, we report new limits on 21 cm emission from cosmic reionization based on a 135 day observing campaign with a 64-element deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization in South Africa. This work extends the work presented in Parsons et al. with more collecting area, a longer observing period, improved redundancy-based calibration, improved fringe-rate filtering, and updated power-spectral analysis using optimal quadratic estimators. The result is a new 2σ upper limit on Δ 2 (k) of (22.4 mK) 2 in the range k h 0.15 0.5 Mpc 1 < < -at z = 8.4. This represents a three-fold improvement over the previous best upper limit. As we discuss in more depth in a forthcoming paper, this upper limit supports and extends previous evidence against extremely cold reionization scenarios. We conclude with a discussion of implications for future 21 cm reionization experiments, including the newly funded Hydrogen Epoch of Reionization Array.

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Section: Calibrationmentioning

confidence: 70%

PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM ATz= 8.4

Ali

Parsons

Zheng

et al. 2015

ApJ

Self Cite

265

224

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show abstract

“…The reionization signals are of 10-100 mK brightness temperature, whereas the foregrounds are 100s to 10,000s of K; the spectral dynamic range required for the detection of the global EoR signature in any measurement of the absolute spectrum of the radio sky is about 10 3 -10 6 . It is therefore not surprising that considerable effort has been placed on the development of methods for the separation of the faint 21-cm signals from the substantially brighter foreground component in measurement data in the context of detection of both the global and statistical EoR signals (see, for example, Gnedin & Shaver 2004;Morales et al 2006;Vedantham et al 2012;Liu et al 2013;Thyagarajan et al 2013;Harker 2015;Bernardi et al 2016;Chapman et al 2016;Nhan et al 2017). …”

Section: Introductionmentioning

confidence: 99%

Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

Rao

Subrahmanyan

Shankar

et al. 2017

ApJ

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Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts 30-6 and appear at meter wavelengths as a tiny CMB distortion along with the Galactic and extragalactic radio sky, which is orders of magnitude brighter. Therefore, detection requires precise methods to model foregrounds. We present a method of foreground fitting using maximally smooth (MS) functions. We demonstrate the usefulness of MS functions over traditionally used polynomials to separate foregrounds from the Epoch of Reionization (EoR) signal. We also examine the level of spectral complexity in plausible foregrounds using GMOSS, a physically motivated model of the radio sky, and find that they are indeed smooth and can be modeled by MS functions to levels sufficient to discern the vanilla model of the EoR signal. We show that MS functions are loss resistant and robustly preserve EoR signal strength and turning points in the residuals. Finally, we demonstrate that in using a well-calibrated spectral radiometer and modeling foregrounds with MS functions, the global EoR signal can be detected with a Bayesian approach with 90% confidence in 10 minutes' integration.

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“…Datta et al 2010) show that the foreground contribution to the Cylindrical Power Spectrum P (k ⊥ , k ) is expected to be restricted within a wedge in the two dimensional (2D) (k ⊥ , k ) plane. The idea in Foreground Avoidance is to avoid the Fourier modes within the foreground wedge and only use the uncontaminated modes outside the wedge to estimate the 21-cm power spectrum (Vedantham et al 2012;Thyagarajan et al 2013;Pober et al 2014;Liu et al 2014a,b;Dillon et al 2014Dillon et al , 2015Ali et al 2015). In a recent paper Jacobs et al (2016) have compared several power spectrum estimation techniques in the context of MWA.…”

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confidence: 99%

The visibility-based tapered gridded estimator (TGE) for the redshifted 21-cm power spectrum

Choudhuri¹,

Bharadwaj²,

Chatterjee³

et al. 2016

Mon. Not. R. Astron. Soc.

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We present the improved visibility based Tapered Gridded Estimator (TGE) for the power spectrum of the diffuse sky signal. The visibilities are gridded to reduce the computation, and tapered through a convolution to suppress the contribution from the outer regions of the telescope's field of view. The TGE also internally estimates the noise bias, and subtracts this out to give an unbiased estimate of the power spectrum. An earlier version of the 2D TGE for the angular power spectrum C ℓ is improved and then extended to obtain the 3D TGE for the power spectrum P (k) of the 21-cm brightness temperature fluctuations. Analytic formulas are also presented for predicting the variance of the binned power spectrum. The estimator and its variance predictions are validated using simulations of 150 MHz GMRT observations. We find that the estimator accurately recovers the input model for the 1D Spherical Power Spectrum P (k) and the 2D Cylindrical Power Spectrum P (k ⊥ , k ), and the predicted variance is also in reasonably good agreement with the simulations.

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A Study of Fundamental Limitations to Statistical Detection of Redshifted H I From the Epoch of Reionization

Cited by 155 publications

References 55 publications

PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM ATz= 8.4

PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM ATz= 8.4

Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

The visibility-based tapered gridded estimator (TGE) for the redshifted 21-cm power spectrum

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