A Simulation Framework for the LiteBIRD Instruments

TL;DR

The paper introduces LBS, a Python-based simulation framework for modeling LiteBIRD's instruments and data acquisition process, aiding in performance assessment and pipeline development for cosmic background radiation studies.

Contribution

It presents a comprehensive simulation framework for LiteBIRD instruments, enabling realistic modeling of observations, noise, and systematic errors, with a complete pipeline for performance evaluation.

Findings

First simulation run demonstrates the pipeline's capability to reproduce expected instrument performance.

LBS enables accurate and reproducible pipeline development for LiteBIRD data analysis.

Framework supports modeling of sky signals, noise, and systematic effects for primordial cosmology research.

Abstract

LiteBIRD, the Lite (Light) satellite for the study of $B$-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission focused on primordial cosmology and fundamental physics. In this paper, we present the LiteBIRD Simulation Framework (LBS), a Python package designed for the implementation of pipelines that model the outputs of the data acquisition process from the three instruments on the LiteBIRD spacecraft: LFT (Low-Frequency Telescope), MFT (Mid-Frequency Telescope), and HFT (High-Frequency Telescope). LBS provides several modules to simulate the scanning strategy of the telescopes, the measurement of realistic polarized radiation coming from the sky (including the Cosmic Microwave Background itself, the Solar and Kinematic dipole, and the diffuse foregrounds emitted by the Galaxy), the generation of instrumental noise and the effect of systematic errors, like pointing wobbling, non-idealities in the Half-Wave Plate, et cetera. Additionally, we present the implementation of a simple but complete pipeline that showcases the main features of LBS. We also discuss how we ensured that LBS lets people develop pipelines whose results are accurate and reproducible. A full end-to-end pipeline has been developed using LBS to characterize the scientific performance of the LiteBIRD experiment. This pipeline and the results of the first simulation run are presented in Puglisi et al. (2025).