The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation

Offringa, A. R. ; Wayth, R. B. ; Hurley-Walker, N. ; Kaplan, D. L. ; Barry, N. ; Beardsley, A. P. ; Bell, M. E. ; Bernardi, G. ; Bowman, J. D. ; Briggs, F. ; Callingham, J. R. ; Cappallo, R. J. ; Carroll, P. ; Deshpande, A. A. ; Dillon, J. S. ; Dwarakanath, K. S. ; Ewall-Wice, A. ; Feng, L. ; For, B.-Q. ; Gaensler, B. M. ; Greenhill, L. J. ; Hancock, P. ; Hazelton, B. J. ; Hewitt, J. N. ; Hindson, L. ; Jacobs, D. C. ; Johnston-Hollitt, M. ; Kapińska, A. D. ; Kim, H.-S. ; Kittiwisit, P. ; Lenc, E. ; Line, J. ; Loeb, A. ; Lonsdale, C. J. ; McKinley, B. ; McWhirter, S. R. ; Mitchell, D. A. ; Morales, M. F. ; Morgan, E. ; Morgan, J. ; Neben, A. R. ; Oberoi, D. ; Ord, S. M. ; Paul, S. ; Pindor, B. ; Pober, J. C. ; Prabu, T. ; Procopio, P. ; Riding, J. ; Udaya Shankar, N. ; Sethi, S. ; Srivani, K. S. ; Staveley-Smith, L. ; Subrahmanyan, R. ; Sullivan, I. S. ; Tegmark, M. ; Thyagarajan, N. ; Tingay, S. J. ; Trott, C. M. ; Webster, R. L. ; Williams, A. ; Williams, C. L. ; Wu, C. ; Wyithe, J. S. ; Zheng, Q. (2015) The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation Publications of the Astronomical Society of Australia, 32 . Article ID e008. ISSN 1323-3580

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Official URL: https://www.cambridge.org/core/journals/publicatio...

Related URL: http://dx.doi.org/10.1017/pasa.2015.7

Abstract

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).

Item Type:Article
Source:Copyright of this article belongs to Cambridge University Press.
Keywords:Instrumentation: Interferometers; Methods: Observationall Radio Continuum: General; Techniques: Interferometric
ID Code:114277
Deposited On:21 May 2018 09:09
Last Modified:21 May 2018 09:09

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