Planck intermediate results. LVII. Joint Planck LFI and HFI data processing

TL;DR

The paper introduces the NPIPE processing pipeline for Planck data, significantly reducing noise and systematics, and provides new measurements of the Solar dipole and reionization optical depth using combined LFI and HFI data.

Contribution

It presents a new data processing pipeline that improves calibration, reduces noise, and enhances consistency in Planck frequency maps, enabling more precise cosmological measurements.

Findings

First estimate of the Solar dipole amplitude from combined frequencies.

Updated optical depth of reionization: τ = 0.051 ± 0.006.

Comprehensive simulations including full time-domain processing.

Abstract

We present the NPIPE processing pipeline, which produces calibrated frequency maps in temperature and polarization from data from the Planck Low Frequency Instrument (LFI) and High Frequency Instrument (HFI) using high-performance computers. NPIPE represents a natural evolution of previous Planck analysis efforts, and combines some of the most powerful features of the separate LFI and HFI analysis pipelines. The net effect of the improvements is lower levels of noise and systematics in both frequency and component maps at essentially all angular scales, as well as notably improved internal consistency between the various frequency channels. Based on the NPIPE maps, we present the first estimate of the Solar dipole determined through component separation across all nine Planck frequencies. The amplitude is ($3366.6 \pm 2.7$)$\mu$K, consistent with, albeit slightly higher than, earlier estimates. From the large-scale polarization data, we derive an updated estimate of the optical depth of reionization of $\tau = 0.051 \pm 0.006$, which appears robust with respect to data and sky cuts. There are 600 complete signal, noise and systematics simulations of the full-frequency and detector-set maps. As a Planck first, these simulations include full time-domain processing of the beam-convolved CMB anisotropies. The release of NPIPE maps and simulations is accompanied with a complete suite of raw and processed time-ordered data and the software, scripts, auxiliary data, and parameter files needed to improve further on the analysis and to run matching simulations.