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arXiv · 2604.20262

Measuring Tianlai's primary beam using sky model

Yunbo Geng·Furen Deng·Jixia Li·Shifan Zuo·Shijie Sun·Yichao Li·Fengquan Wu·Yougang Wang·Xuelei Chen
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Abstract

We present the beam pattern measurement of the Tianlai Cylinder Pathfinder Array. As it is a pure drift-scan instrument, we exploit the North-South motion of the Sun to demonstrate that the primary beam is factorizable. Leveraging this property, we decompose the primary beam into independent East-West (E-W) and North-South (N-S) components. Using the Sun as a calibration source, we obtain the E-W beam profiles at various elevations, applying normalization to eliminate the effects of solar activity. Subsequently, we simulate the observed signals using a sky map model to derive the best-fit N-S beam. The results of this work are consistent with previous expectations.

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Yunbo Geng, Furen Deng, Jixia Li, Shifan Zuo, Shijie Sun, Yichao Li, Fengquan Wu, Yougang Wang, Xuelei Chen. 2026-04-22. Measuring Tianlai's primary beam using sky model. https://arxiv.org/abs/2604.20262

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