A cross-calibration approach for polarisation-sensitive detectors in CMB experiments: application to LiteBIRD's polarisation angle calibration
Year: 2026
Type: preprint
Abstract: We present a cross-calibration algorithm that determines the relative calibration of detectors within the same frequency band of a CMB experiment. The method iteratively compares single-detector maps with frequency-band maps, and it can be applied to any calibration parameter that can be corrected through reprocessing of the instrument's data at the map level. This allows for validation and correction of calibration both before and after observations. We validate the pipeline by calibrating the polarisation angle of simulated sky maps from the upcoming \textit{LiteBIRD} experiment. The cross-calibration algorithm has been tested both in the case of random miscalibration of each individual detector and in the case of rotation of entire detector wafers. In both cases, the cross-calibration algorithm converges to the correct value and we are able to identify and correct relative miscalibrations in the polarisation angle of each detector with arcminute precision. Absolute calibration can then be addressed either through ground-based measurements, or through the $E$-$B$ nulling technique. To assess compliance with \textit{LiteBIRD}'s systematics budget, we propagate the residual miscalibration uncertainties through component separation and tensor-to-scalar ratio ($r$) estimation pipelines using both parametric (\texttt{FgBuster}) and blind (\texttt{HILC}) methods. In both cases, the induced bias on $r$ remains well below the \textit{LiteBIRD} maximum budget for systematics of $δr < 6.5\times10^{-6}$. This confirms that the cross-calibration method presented is suited for use in modern high-precision CMB experiments.
Source: arXiv (Cornell University)
Authors: Novelli, A., Piacentini, F., Micheli, S., Allys, E., Anand, A., Aumont, J., Banday, A. J., Barreiro, R. B., Bartolo, N., Basak, S., Basyrov, A., Besnard, A., Blinov, D., Bortolami, M., Brinckmann, T., Cacciotti, F., Calabrese, E., Campeti, P., Carones, A., Carralot, F., Casas, F. J., Chandran, J., Cheung, K., Citran, M., Clermont, L., Columbro, F., Coppolecchia, A., Cuttaia, F., de Bernardis, P., de Haan, T., de la Hoz, E., De Lucia, M., Diego-Palazuelos, P., Eriksen, H. K., Finelli, F., Franceschet, C., Fuskeland, U., Galloni, G., Galloway, M., Gerbino, M., Gervasi, M., Génova-Santos, R. T., Ghigna, T., Giardiello, S., Gimeno-Amo, C., Gruppuso, A., Hazumi, M., Henrot-Versillé, S., Hergt, L. T., Hivon, E., Ishino, H., Kohri, K., Lamagna, L., Lattanzi, M., Leloup, C., Levrier, F., Lonappan, A. I., López-Caniego, M., Luzzi, G., Macias-Perez, J., Maranchery, V., Martínez-González, E., Masi, S., Matarrese, S., Matsumura, T., Migliaccio, M., Monelli, M., Morgante, G., Mousset, L., Nagata, R., Namikawa, T., Natoli, P., Noviello, F., Pagano, L., Paiella, A., Paoletti, D., Pascual-Cisneros, G., Patanchon, G., Piccirilli, G., Pinchera, M., Polenta, G., Porcelli, L., Remazeilles, M., Ritacco, A., Ruiz-Granda, M., Sakurai, Y., Salvati, L., Sanghavi, J., Sauvage, V., Scott, D., Shiraishi, M., Signorelli, G., Sullivan, R. M., Takase, Y., Terenzi, L., Tomasi, M., Tristram, M., Vacher, L., van Tent, B., Vielva, P., Vinzl, S., Wehus, I. K., Weymann-Despres, G., Wollack, E. J., Zannoni, M.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: U.S. Department of Energy, National Aeronautics and Space Administration, UK Space Agency, European Commission, Deutsche Forschungsgemeinschaft, Ministry of Education, Culture, Sports, Science and Technology, Swedish National Space Agency, Centro para el Desarrollo Tecnológico Industrial, Centre National d’Etudes Spatiales, Centre National de la Recherche Scientifique, Japan Society for the Promotion of Science, Japan Aerospace Exploration Agency, Agencia Estatal de Investigación
OpenAlex ID: W7165632970