PAPER-64 Constraints on Reionization: The 21cm Power Spectrum at z=8.4

30 Jun 2018  ·  Ali Zaki S., Parsons Aaron R., Zheng Haoxuan, Pober Jonathan C., Liu Adrian, Aguirre James E., Bradley Richard F., Bernardi Gianni, Carilli Chris L., Cheng Carina, DeBoer David R., Dexter Matthew R., Grobbelaar Jasper, Horrell Jasper, Jacobs Daniel C., Klima Pat, MacMahon David H. E., Maree Matthys, Moore David F., Razavi Nima, Stefan Irina I., Walbrugh William P., Walker Andre ·

In this paper, we report new limits on 21cm 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 (PAPER) in South Africa. This work extends the work presented in Parsons et al. (2014) with more collecting area, a longer observing period, improved redundancy-based calibration, optimal fringe-rate filtering, and improved power-spectral analysis using optimal quadratic estimators... The result is a new $2\sigma$ upper limit on $\Delta^{2}(k)$ of (22.4 mK)$^2$ in the range $0.15 < k < 0.5h\ {\rm Mpc}^{-1}$ 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 (Pober et al. 2015, in prep), this upper limit supports and extends previous evidence against extremely cold reionization scenarios. We conclude with a discussion of implications for future 21cm reionization experiments, including the newly funded Hydrogen Epoch of Reionization Array (HERA). $\textbf{The limits presented in this paper have been retracted: The erratum can be found in Appendix A. }$ read more

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Cosmology and Nongalactic Astrophysics