Title:	The low-frequency environment of the Murchison widefield array: radio-frequency interference analysis and mitigation
Authors:	Offringa, A.R. Wayth, R.B. Deshpande, A.A. Paul, S Prabu, T. Udaya Shankar, N. Sethi, S.K. Srivani, K.S. Subrahmanyan, Ravi +25 Co-authors
Issue Date:	3-Mar-2015
Publisher:	Cambridge University Press for Astronomical Society of Australia
Citation:	Publications of the Astronomical Society of Australia,2015,Vol.32, e008
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
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/6241
ISSN:	1323-3580 1448-6083(online)
Alternative Location:	http://adsabs.harvard.edu/abs/2015PASA...32....8O http://arxiv.org/abs/1501.03946 http://dx.doi.org/10.1017/pasa.2015.7
Copyright:	2015 Astronomical Society of Australia
Appears in Collections:	Research Papers (A&A)

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