Journal article

Overcoming real-world obstacles in 21 cm power spectrum estimation: A method demonstration and results from early Murchison Widefield Array data

Joshua S Dillon, Adrian Liu, Christopher L Williams, Jacqueline N Hewitt, Max Tegmark, Edward H Morgan, Alan M Levine, Miguel F Morales, Steven J Tingay, Gianni Bernardi, Judd D Bowman, Frank H Briggs, Roger C Cappallo, David Emrich, Daniel A Mitchell, Divya Oberoi, Thiagaraj Prabu, Randall Wayth, Rachel L Webster



We present techniques for bridging the gap between idealized inverse covariance weighted quadratic estimation of 21 cm power spectra and the real-world challenges presented universally by interferometric observation. By carefully evaluating various estimators and adapting our techniques for large but incomplete data sets, we develop a robust power spectrum estimation framework that preserves the so-called Epoch of Reionization (EoR) window and keeps track of estimator errors and covariances. We apply our method to observations from the 32-tile prototype of the Murchinson Widefield Array to demonstrate the importance of a judicious analysis technique. Lastly, we apply our method to investigat..

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University of Melbourne Researchers


Awarded by U.S. National Science Foundation

Awarded by Australian Research Council (LIEF Grants)

Awarded by U.S. Air Force Office of Scientic Research

Awarded by Centre for All-sky Astrophysics (an Australian Research Council Centre of Excellence)

Awarded by Victoria University of Wellington (New Zealand Ministry of Economic Development)

Awarded by NSF

Funding Acknowledgements

This work makes use of the Murchison Radio-astronomy Observatory. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site. Support for the MWA comes from the U.S. National Science Foundation (Grants No. AST-0457585, No. PHY-0835713, No. CAREER-0847753, and No. AST-0908884), the Australian Research Council (LIEF Grants No. LE0775621 and No. LE0882938), the U.S. Air Force Office of Scientic Research (Grant No. FA9550-0510247), and the Centre for All-sky Astrophysics (an Australian Research Council Centre of Excellence funded by Grant No. CE110001020). Support is also provided by the Smithsonian Astrophysical Observatory, the MIT School of Science, the Raman Research Institute, the Australian National University, and the Victoria University of Wellington (via Grant No. MED-E1799 from the New Zealand Ministry of Economic Development and an IBM Shared University Research Grant). The Australian Federal government provides additional support via the National Collaborative Research Infrastructure Strategy, Education Investment Fund, and the Australia India Strategic Research Fund, and Astronomy Australia Limited, under contract to Curtin University. We acknowledge the iVEC Petabyte Data Store, the Initiative in Innovative Computing and the CUDA Center for Excellence sponsored by NVIDIA at Harvard University, and the International Centre for Radio Astronomy Research (ICRAR), a Joint Venture of Curtin University and The University of Western Australia, funded by the Western Australian State government. Additionally, the authors wish to thank Aaron Ewall-Wice, Lu Feng, Abraham Neben, Aaron Parsons, Jonathan Pober, Ronald Remillard, and Richard Shaw for valuable discussions, and Rennan Barkana for both useful discussions and providing the theory results shown in Figs. 7 and 8. This work is partially supported by NSF Grants No. AST-0821321 and No. AST-1105835. A. L. acknowledges support from the Berkeley Center for Cosmological Physics. Because the contributions of the first two authors were essentially equal, we determined their order by a Monte Carlo algorithm inspired by the one presented in Sec. II B.