EOVSA Implementation of a Spectral Kurtosis Correlator for Transient Detection and Classification

We describe in general terms the practical use in astronomy of a higher-order statistical quantity called spectral kurtosis (SK), and describe the first implementation of SK-enabled firmware in the Fourier transform-engine (F-engine) of a digital FX correlator for the Expanded Owens Valley Solar Array (EOVSA). The development of the theory for SK is summarized, leading to an expression for generalized SK that is applicable to both SK spectrometers and those not specifically designed for SK. We also give the means for computing both the SK estimator and thresholds for its application as a discriminator of RFI contamination. Tests of the performance of EOVSA as an SK spectrometer are shown to agree precisely with theoretical expectations, and the methods for configuring the correlator for correct SK operation are described.