On Denoising Crosstalk in Radio Interferometry

Noise reduction in radio interferometers is a formidable task due to the relatively weak signals under observation. The usual strategy is to compensate with a large number of antennas and extend the observation time. We showed recently that one could denoise directly antenna time-series, under the assumption of uncorrelated noise. This work is a first step to extend it for when crosstalk is present. We first propose a subspace based algorithm to estimate noise covariance, and then demonstrate that the noise covariance can be accurately estimated, and the image denoised. We show sky images generated using a core station LOFAR, and that even with one tenth the observation time (and thus one tenth the data) the estimate can still be enhanced.