Crab nebula at 260 GHz with the NIKA2 polarimeter. Implications for the polarization angle calibration of future CMB experiments

TL;DR

This paper presents polarization measurements of the Crab nebula at 260 GHz using NIKA2, aiming to improve polarization angle calibration for future CMB experiments crucial for detecting primordial gravitational waves.

Contribution

It provides high-frequency polarization data of the Crab nebula with NIKA2 and discusses its implications for enhancing polarization angle calibration accuracy in CMB studies.

Findings

Crab nebula exhibits a high polarized signal at 260 GHz.

Measurement accuracy can significantly improve polarization angle calibration.

Results inform calibration strategies for next-generation CMB experiments.

Abstract

The quest for primordial gravitational waves enclosed in the Cosmic Microwave Background (CMB) polarization B-modes signal motivates the development of a new generation of high sensitive experiments (e.g. CMB-S4, LiteBIRD) that would allow them to detect its imprint.Neverthless, this will be only possible by ensuring a high control of the instrumental systematic effects and an accurate absolute calibration of the polarization angle. The Crab nebula is known to be a polarization calibrator on the sky for CMB experiments, already used for the Planck satellite it exhibits a high polarized signal at microwave wavelengths. In this work we present Crab polarization observations obtained at the central frequency of 260 GHz with the NIKA2 instrument and discuss the accuracy needed on such a measurement to improve the constraints on the absolute angle calibration for CMB experiments.