Journal article

Quantifying ionospheric effects on time-domain astrophysics with the Murchison Widefield Array

Shyeh Tjing Loi, Tara Murphy, Martin E Bell, David L Kaplan, Emil Lenc, Andre R Offringa, Natasha Hurley-Walker, G Bernardi, JD Bowman, F Briggs, RJ Cappallo, BE Corey, AA Deshpande, D Emrich, BM Gaensler, R Goeke, LJ Greenhill, BJ Hazelton, M Johnston-Hollitt, JC Kasper Show all

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | OXFORD UNIV PRESS | Published : 2015

Abstract

Refraction and diffraction of incoming radio waves by the ionosphere induce time variability in the angular positions, peak amplitudes and shapes of radio sources, potentially complicating the automated cross-matching and identification of transient and variable radio sources. In this work, we empirically assess the effects of the ionosphere on data taken by the Murchison Widefield Array (MWA) radio telescope. We directly examine 51 h of data observed over 10 nights under quiet geomagnetic conditions (global storm index Kp < 2), analysing the behaviour of short-time-scale angular position and peak flux density variations of around ten thousand unresolved sources. We find that while much of t..

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University of Melbourne Researchers

Grants

Awarded by US National Science Foundation


Awarded by Australian Research Council (LIEF)


Awarded by US Air Force Office of Scientific Research


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


Awarded by Victoria University of Wellington from the New Zealand Ministry of Economic Development


Awarded by Direct For Mathematical & Physical Scien


Funding Acknowledgements

We thank J.-P. Macquart and J. Morgan for useful discussions. 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 US National Science Foundation (grants AST-0457585, PHY-0835713, CAREER-0847753, AST-0908884 and AST-1412421), the Australian Research Council (LIEF grants LE0775621 and LE0882938), the US 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 MIT School of Science, 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.