An On-Sky Atmospheric Calibration of SPT-SLIM

K. R. Dibert; M. Adamic; A. J. Anderson; P. S. Barry; B. A. Benson; C. S. Benson; E. Brooks; J. E. Carlstrom; T. Cecil; C. L. Chang; M. Dobbs; K. Fichman; K. S. Karkare; G. K. Keating; A. M. Lapuente; M. Lisovenko; D. P. Marrone; J. Montgomery; T. Natoli; Z. Pan; A. Rahlin; G. Robson; M. Rouble; G. Smecher; V. Yefremenko; M. R. Young; C. Yu; J. A. Zebrowski; C. Zhang

arXiv · 2510.14220

An On-Sky Atmospheric Calibration of SPT-SLIM

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Abstract

We present the methodology and results of the on-sky responsivity calibration of the South Pole Telescope Shirokoff Line Intensity Mapper (SPT-SLIM). SPT-SLIM is a pathfinder line intensity mapping experiment utilizing the on-chip spectrometer technology, and was first deployed during the 2024-2025 Austral Summer season on the South Pole Telescope. During the two-week on-sky operation of SPT-SLIM, we performed periodic measurements of the detector response as a function of the telescope elevation angle. Combining these data with atmospheric opacity measurements from an on-site atmospheric tipping radiometer, simulated South Pole atmospheric spectra, and measured detector spectral responses, we construct estimates for the responsivity of SPT-SLIM detectors to sky loading. We then use this model to calibrate observations of the moon taken by SPT-SLIM, cross-checking the result against the known brightness temperature of the Moon as a function of its phase.

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K. R. Dibert, M. Adamic, A. J. Anderson, P. S. Barry, B. A. Benson, C. S. Benson, E. Brooks, J. E. Carlstrom, T. Cecil, C. L. Chang, M. Dobbs, K. Fichman, K. S. Karkare, G. K. Keating, A. M. Lapuente, M. Lisovenko, D. P. Marrone, J. Montgomery, T. Natoli, Z. Pan, A. Rahlin, G. Robson, M. Rouble, G. Smecher, V. Yefremenko, M. R. Young, C. Yu, J. A. Zebrowski, C. Zhang. 2025-10-16. An On-Sky Atmospheric Calibration of SPT-SLIM. https://arxiv.org/abs/2510.14220

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