The Low-Frequency Environment of the Murchison Widefield Array: Radio-Frequency Interference Analysis and Mitigation

A.R. Offringa, R.B. Wayth, N. Hurley-Walker, D.L. Kaplan, N. Barry, A.P. Beardsley, M.E. Bell, G. Bernardi, J.D. Bowman, F. Briggs, J.R. Callingham, R.J. Cappallo, P. Carroll, A.A. Deshpande, J.S. Dillon, K.S. Dwarakanath, A. Ewall-Wice, L. Feng, Bi-Qing For, B.M. GaenslerL.J. Greenhill, P. Hancock, B.J. Hazelton, J.N. Hewitt, L. Hindson, D.C. Jacobs, M. Johnston-Hollitt, Anna Kapińska, H.S. Kim, P. Kittiwisit, E. Lenc, J. Line, A. Loeb, C.J. Lonsdale, B. Mckinley, S.R. Mcwhirter, D.A. Mitchell, M.F. Morales, E. Morgan, J. Morgan, A.R. Neben, D. Oberoi, S.M. Ord, S. Paul, B. Pindor, J.C. Pober, T. Prabu, P. Procopio, J. Riding, N. Udaya Shankar, S. Sethi, K.S. Srivani, Lister Staveley-Smith, R. Subrahmanyan, I.S. Sullivan, M. Tegmark, N. Thyagarajan, S.J. Tingay, C.M. Trott, R.L. Webster, A. Williams, C.L. Williams, Chen Wu, J.S. Wyithe, Q. Zheng

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    123 Citations (Web of Science)


    © 2015 Astronomical Society of Australia. The Murchison Widefield Array is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array. We describe the automated radio-frequency interference detection strategy implemented for the Murchison Widefield Array, which is based on the aoflagger platform, and present 72-231 MHz radio-frequency interference statistics from 10 observing nights. Radio-frequency interference detection removes 1.1% of the data. Radio-frequency interference from digital TV is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After radio-frequency interference detection and excision, almost all data can be calibrated and imaged without further radio-frequency interference mitigation efforts, including observations within the FM and digital TV bands. The results are compared to a previously published Low-Frequency Array radio-frequency interference survey. The remote location of the Murchison Widefield Array results in a substantially cleaner radio-frequency interference environment compared to Low-Frequency Array's radio environment, but adequate detection of radio-frequency interference is still required before data can be analysed. We include specific recommendations designed to make the Square Kilometre Array more robust to radio-frequency interference, including: the availability of sufficient computing power for radio-frequency interference detection; accounting for radio-frequency interference in the receiver design; a smooth band-pass response; and the capability of radio-frequency interference detection at high time and frequency resolution (second and kHz-scale respectively).
    Original languageEnglish
    Pages (from-to)e008
    JournalPublications of the Astronomical Society of Australia
    Publication statusPublished - 2015


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