In-flight polarization angle calibration for LiteBIRD: blind challenge and cosmological implications
Abstract
We present a demonstration of the in-flight polarization angle calibration for the JAXA/ISAS second strategic large class mission, LiteBIRD, and estimate its impact on the measurement of the tensor-to-scalar ratio parameter, r, using simulated data. We generate a set of simulated sky maps with CMB and polarized foreground emission, and inject instrumental noise and polarization angle offsets to the 22 (partially overlapping) LiteBIRD frequency channels. Our in-flight angle calibration relies on nulling the EB cross correlation of the polarized signal in each channel. This calibration step has been carried out by two independent groups with a blind analysis, allowing an accuracy of the order of a few arc-minutes to be reached on the estimate of the angle offsets. Both the corrected and uncorrected multi-frequency maps are propagated through the foreground cleaning step, with the goal of computing clean CMB maps. We employ two component separation algorithms, the Bayesian-Separation of Components and Residuals Estimate Tool (B-SeCRET), and the Needlet Internal Linear Combination (NILC). We find that the recovered CMB maps obtained with algorithms that do not make any assumptions about the foreground properties, such as NILC, are only mildly affected by the angle miscalibration. However, polarization angle offsets strongly bias results obtained with the parametric fitting method. Once the miscalibration angles are corrected by EB nulling prior to the component separation, both component separation algorithms result in an unbiased estimation of the r parameter. While this work is motivated by the conceptual design study for LiteBIRD, its framework can be broadly applied to any CMB polarization experiment. In particular, the combination of simulation plus blind analysis provides a robust forecast by taking into account not only detector sensitivity but also systematic effects.
Cite
@article{arxiv.2111.09140,
title = {In-flight polarization angle calibration for LiteBIRD: blind challenge and cosmological implications},
author = {Nicoletta Krachmalnicoff and Tomotake Matsumura and Elena de la Hoz and Soumen Basak and Alessandro Gruppuso and Yuto Minami and Carlo Baccigalupi and Eiichiro Komatsu and Enrique Martínez-González and Patricio Vielva and Jonathan Aumont and Ragnhild Aurlien and Susanna Azzoni and Anthony J. Banday and Rita B. Barreiro and Nicola Bartolo and Marco Bersanelli and Erminia Calabrese and Alessandro Carones and Francisco J. Casas and Kolen Cheung and Yuji Chinone and Fabio Columbro and Paolo de Bernardis and Patricia Diego-Palazuelos and Josquin Errard and Fabio Finelli and Unni Fuskeland and Mathew Galloway and Ricardo T. Genova-Santos and Martina Gerbino and Tommaso Ghigna and Serena Giardiello and Eirik Gjerløw and Masashi Hazumi and Sophie Henrot-Versillé and Theodore Kisner and Luca Lamagna and Massimiliano Lattanzi and François Levrier and Gemma Luzzi and Davide Maino and Silvia Masi and Marina Migliaccio and Ludovic Montier and Gianluca Morgante and Baptiste Mot and Ryo Nagata and Federico Nati and Paolo Natoli and Luca Pagano and Alessandro Paiella and Daniela Paoletti and Guillaume Patanchon and Francesco Piacentini and Gianluca Polenta and Davide Poletti and G. Puglisi and Mathieu Remazeilles and Jose Alberto Rubino-Martin and Manami Sasaki and Maresuke Shiraishi and Giovanni Signorelli and Samantha Stever and Andrea Tartari and Matthieu Tristram and Masatoshi Tsuji and Léo Vacher and Ingunn K. Wehus and Mario Zannoni},
journal= {arXiv preprint arXiv:2111.09140},
year = {2022}
}
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Submitted to JCAP