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arXiv · 1910.07956

Design, operation and performance of the PAON4 prototype transit interferometer

R. Ansari·J. E Campagne·D. Charlet·M. Moniez·C. Pailler·O. Perdereau·M. Taurigna·J. M. Martin·F. Rigaud·P. Colom·Ph. Abbon·Ch. Magneville·J. Pezzani·C. Viou·S. A. Torchinsky·Q. Huang·J. Zhang
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Abstract

PAON4 is an L-band (1250-1500 MHz) small interferometer operating in transit mode deployed at the Nan\c{c}ay observatory in France, designed as a prototype instrument for Intensity Mapping. It features four 5~meter diameter dishes in a compact triangular configuration, with a total geometric collecting area of $\sim75 \mathrm{m^2}$, and equipped with dual polarization receivers. A total of 36 visibilities are computed from the 8 independent RF signals by the software correlator over the full 250~MHz RF band. The array operates in transit mode, with the dishes pointed toward a fixed declination, while the sky drifts across the instrument. Sky maps for each frequency channel are then reconstructed by combining the time-dependent visibilities from the different baselines observed at different declinations. This paper presents an overview of the PAON4 instrument design and goals, as a prototype for dish arrays to map the Large Scale Structure in radio, using intensity mapping of the atomic hydrogen $21~\mathrm{cm}$ line. We operated PAON4 over several years and use data from observations in different periods to assess the array performance. We present preliminary analysis of a large fraction of this data and discuss crucial issues for this type of instrument, such as the calibration strategy, instrument response stability, and noise behaviour.

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R. Ansari, J. E Campagne, D. Charlet, M. Moniez, C. Pailler, O. Perdereau, M. Taurigna, J. M. Martin, F. Rigaud, P. Colom, Ph. Abbon, Ch. Magneville, J. Pezzani, C. Viou, S. A. Torchinsky, Q. Huang, J. Zhang. 2019-10-17. Design, operation and performance of the PAON4 prototype transit interferometer. https://doi.org/10.1093/mnras%2Fstaa345

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