Journal article
First limits on the 21 cm power spectrum during the Epoch of X-ray heating
A Ewall-Wice, JS Dillon, JN Hewitt, A Loeb, A Mesinger, AR Neben, AR Offringa, M Tegmark, N Barry, AP Beardsley, G Bernardi, JD Bowman, F Briggs, RJ Cappallo, P Carroll, BE Corey, A de Oliveira-Costa, D Emrich, L Feng, BM Gaensler Show all
Monthly Notices of the Royal Astronomical Society | OXFORD UNIV PRESS | Published : 2016
Abstract
We present first results from radio observations with the Murchison Widefield Array seeking to constrain the power spectrum of 21 cm brightness temperature fluctuations between the redshifts of 11.6 and 17.9 (113 and 75 MHz). 3 h of observations were conducted over two nights with significantly different levels of ionospheric activity. We use these data to assess the impact of systematic errors at low frequency, including the ionosphere and radio-frequency interference, on a power spectrum measurement. We find that after the 1-3 h of integration presented here, our measurements at the Murchison Radio Observatory are not limited by RFI, even within the FMband, and that the ionosphere does not..
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Grants
Awarded by Australian Research Council
Funding Acknowledgements
We would like to thank the referees for their helpful comments. We extend our gratitude to Jeff Zhang and Adrian Liu for useful discussions. This work was supported by NSF Grants AST-0457585, AST-0821321, AST-1105835, AST-1410719, AST-1410484, AST-1411622, and AST-1440343, by the MIT School of Science, by the Marble Astrophysics Fund, and by generous donations from Jonathan Rothberg and an anonymous donor. AEW acknowledges support from the National Science Foundation Graduate Research Fellowship under Grant No. 1122374. AM acknowledges support from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 638809 - AIDA).r This scientific work makes use of the Murchison Radio astronomy Observatory, operated by CSIRO. 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 AST-0457585, PHY-0835713, CAREER 0847753, and AST-0908884), the Australian Research Council (LIEF grants LE0775621 and LE0882938), the U.S. Air Force Office of Scientific Research (grant FA9550-0510247), and the Centre for All-sky Astrophysics (an Australian Research Council Centre of Excellence funded by grant CE110001020). Support is also provided by the Smithsonian Astrophysical Observatory, the Raman Research Institute, the Australian National University, and the Victoria University of Wellington (via grant 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 Commonwealth Scientific and Industrial Research Organisation (CSIRO), 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.