We use time-domain simulations of Jupiter observations to test and develop a beam reconstruction pipeline for the Simons Observatory Small Aperture Telescopes. The method relies on a map maker that estimates and subtracts correlated atmospheric noise and a beam fitting code designed to compensate for the bias caused by the map maker. We test our reconstruction performance for four different frequency bands against various algorithmic parameters, atmospheric conditions and input beams. We additionally show the reconstruction quality as function of the number of available observations and investigate how different calibration strategies affect the beam uncertainty. For all of the cases considered, we find good agreement between the fitted results and the input beam model within a ~1.5% error for a multipole range l = 30 - 700 and an ~0.5% error for a multipole range l = 50 - 200. We conclude by using a harmonic-domain component separation algorithm to verify that the beam reconstruction errors and biases observed in our analysis do not significantly bias the Simons Observatory r-measurement.
@article{arxiv.2304.08995,
title = {The Simons Observatory: Beam characterization for the Small Aperture Telescopes},
author = {Nadia Dachlythra and Adriaan J. Duivenvoorden and Jon E. Gudmundsson and Matthew Hasselfield and Gabriele Coppi and Alexandre E. Adler and David Alonso and Susanna Azzoni and Grace E. Chesmore and Giulio Fabbian and Ken Ganga and Remington G. Gerras and Andrew H. Jaffe and Bradley R. Johnson and Brian Keating and Reijo Keskitalo and Theodore S. Kisner and Nicoletta Krachmalnicoff and Marius Lungu and Frederick Matsuda and Sigurd Naess and Lyman Page and Roberto Puddu and Giuseppe Puglisi and Sara M. Simon and Grant Teply and Tran Tsan and Edward J. Wollack and Kevin Wolz and Zhilei Xu},
journal= {arXiv preprint arXiv:2304.08995},
year = {2024}
}