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

By Z. Ali, Aaron Parsons, Haoxuan Zheng, Jonathan C. Pober, Adrian Liu, J. Aguirre, R. Bradley, G. Bernardi, C. Carilli, Carina Cheng and 13 more. 2015

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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 Δ2(k) of (22.4 mK)2 in the range 0.15 < k < 0.5 h 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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/37139aadd4759cf80b8de25cb991d7e1ce2aa8ae

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Citations in the corpus

Upper Limits on the 21 cm Epoch of Reionization Power Spectrum from One Night with LOFAR (2017, methodology): “The PAPER project provided the tightest upper limit yet of ∆221 < (22.4 mK) 2 in the wave number range 0.15 ≤ k ≤ 0.5 h cMpc−1 at z = 8.4 (Ali et al. 2015).”
FIRST SEASON MWA EOR POWER SPECTRUM RESULTS AT REDSHIFT 7 (2016, methodology): “Using the first generation of instruments, several upper limits have been placed on the 21 cm EoR signal (Ali et al. 2015; Dillon et al. 2014; Parsons et al. 2014; Jacobs et al. 2015; Paciga et al. 2013).”
Hydrogen Epoch of Reionization Array (HERA) (2016, methodology): “Deep integrations also show us that, to the limits of current sensitivity, intrinsic foreground emission is absent outside of the wedge; it can only appear there through instrumental leakage (Parsons et al. 2014; Ali et al. 2015; Moore et al. 2016; Kohn et al. 2016; Thyagarajan et al. 2016).”
The Evolution of the Intergalactic Medium (2015, background): “The number of publications quoting upper bounds on the 21 cm power spectrum has been rapidly increasing in recent years (most recently for the GMRT, PAPER, and MWA efforts in Paciga et al. 2013; Ali et al. 2015; Dillon et al. 2015, respectively).”
Fundamental physics with the Square Kilometre Array (2018, background): “In parallel, several new radio interferometers — LOFAR, PAPER, MWA, HERA — are targeting the spatial fluctuations of the 21 cm signal, due to the ionised bubbles during cosmic reionisation as well as Lyman-α fluctuations (Barkana & Loeb, 2005b) and X-ray heating fluctuations (Pritchard & Furlanetto,”
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, background): “The PAPER collaboration reported a very deep upper limit (Ali et al. 2015), but after re-analysis (Cheng et al. 2018) have recently reported revised and higher upper limits (Kolopanis et al. 2019), the deepest being ∆221 < (200mK) 2 at z = 8.37 and k ≈ 0.37h cMpc−1.”
Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects (2018, background): “Even if current experiments have not yet detected the 21 cm cosmological signature, the PAPER collaboration has recently improved the previous upper limits at z = 8.4 (Ali et al., 2015).”
Charting the parameter space of the global 21-cm signal (2016, background): “Some of our initial models were in conflict with recent upper limits on the 21-cm power spectrum reported by the PAPER collaboration (Ali et al. 2015).”
Enhanced Global Signal of Neutral Hydrogen Due to Excess Radiation at Cosmic Dawn (2018, background): “The predicted strengths of the fluctuation power at z = 8.4 are well below the recent limit from the Precision Array for Probing the Epoch of Reionization (PAPER), leaving a broad parameter space for the excess fraction (Ali et al. 2015).”