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|Title:||Removal and replacement of interference in tied-array radio pulsar observations using the spectral kurtosis estimator||Authors:||Purver,n M.
Bassa, C. G.
Janssen, G. H.
Lee, K. J.
McKee, J. W.
Stappers, B. W.
|Issue Date:||2022||Journal:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY||Number:||510||Issue:||2||First Page:||1597||Abstract:||We describe how to implement the spectral kurtosis method of interference removal (zapping) on a digitized signal of averaged power values. Spectral kurtosis is a hypothesis test, analogous to the t-test, with a null hypothesis that the amplitudes from which power is formed belong to a `good' distribution -- typically Gaussian with zero mean -- where power values are zapped if the hypothesis is rejected at a specified confidence level. We derive signal-to-noise ratios (SNRs) as a function of amount of zapping for folded radio pulsar observations consisting of a sum of signals from multiple telescopes in independent radio-frequency interference (RFI) environments, comparing four methods to compensate for lost data with coherent (tied-array) and incoherent summation. For coherently summed amplitudes, scaling amplitudes from non-zapped telescopes achieves a higher SNR than replacing zapped amplitudes with artificial noise. For incoherently summed power values, the highest SNR is given by scaling power from non-zapped telescopes to maintain a constant mean. We use spectral kurtosis to clean a tied-array radio pulsar observation by the Large European Array for Pulsars (LEAP): the signal from one telescope is zapped with time and frequency resolutions of 6.25 $\mu$s and 0.16 MHz, removing interference along with 0.27 per cent of `good' data, giving an uncertainty of 0.25 $\mu$s in pulse time of arrival (TOA) for PSR J1022+1001. We use a single-telescope observation to demonstrate recovery of the pulse profile shape, with 0.6 per cent of data zapped and a reduction from 1.22 to 0.70 $\mu$s in TOA uncertainty.||URI:||http://hdl.handle.net/20.500.12386/31844||URL:||https://academic.oup.com/mnras/article-abstract/510/2/1597/6445038?redirectedFrom=fulltext&login=true
|Appears in Collections:||1.01 Articoli in rivista|
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checked on Sep 27, 2022
checked on Sep 27, 2022
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