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