| Description: | The NenuFAR project is a new low-frequency instrument (10-85 MHz) currently being built in Nancay, France. In its final specification, it will comprise 96 beam-formed stations included in a 400 m diameter disk and 6 remote stations giving a maximum baseline of ~3 km. The compactness of the instrument makes the instruments ideal to explore the Cosmic Dawn using the 21-cm line of neutral hydrogen (z ~ 30 - 14 corresponding to 45 - 95 MHz). This key era of the history of our Universe saw the first stars, galaxies and black holes appear. This is the aim of the NenuFAR Cosmic Dawn Key Project. The team started observation the 13th of July in a first phase that will characterize the foregrounds around the North Celestial Pole, before starting deep field integration 1st of June of this year with a new COBALT2.0 like correlator (nicknamed NICKEL) currently being set up in Nancay.
The animated image shows Stokes I 40x40 degrees images centred on the North Celestial Pole as seen by NenuFAR at four frequencies ranges. For comparison, an AARTFAAC HBA image at 122.1 MHz produced by Bharat Gehlot is also included. The current 400-meter maximum baseline of NenuFAR limits the resolution to 1.2 degrees at the lowest frequency and 0.5 degrees at the highest frequency. The upcoming addition of remote mini-arrays to NenuFAR will push the resolution down to 4 arcmins at 85 MHz. Despite the very different resolution and Field of View, the similarities in the images are striking. The smallest baselines were included in making these images at which large-scale diffuse Galactic emission, clearly and consistently seen in these images, starts to dominate. Modelling and including this diffuse emission in the calibration sky-model can significantly enhance the calibration of the instrument.
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