Simulating Calibration and Beam Systematics for a Future CMB Space Mission with the TOAST Package

TL;DR

This paper presents a simulation framework using the TOAST package to model and mitigate calibration and beam systematics in future CMB space missions, significantly reducing polarization leakage.

Contribution

It introduces a simulation approach for systematic errors and proposes a template fitting mitigation technique that effectively reduces leakage in CMB polarization measurements.

Findings

Leakage reduced by 2 orders of magnitude at the power spectrum level.

Simulation demonstrates effectiveness of the mitigation technique.

Applicable to realistic satellite mission data, e.g., LiteBIRD.

Abstract

We address in this work the instrumental systematic errors that can potentially affect the forthcoming and future Cosmic Microwave Background experiments aimed at observing its polarized emission. In particular, we focus on the systematics induced by the beam and calibration, which are considered the major sources of leakage from total intensity measurements to polarization. We simulated synthetic data sets with Time-Ordered Astrophysics Scalable Tools, a publicly available simulation and data analysis package. We also propose a mitigation technique aiming at reducing the leakage by means of a template fitting approach. This technique has shown promising results reducing the leakage by 2 orders of magnitude at the power spectrum level when applied to a realistic simulated data set of the LiteBIRD satellite mission.