We analyze the effect of polarized diffuse emission in the calibration of wide-beam mm-wave polarimeters, when using the Crab Nebula as a reference source for both polarized brightness and polarization angle. We show that, for CMB polarization experiments aiming at detecting B-mode in a scenario with a tensor to scalar ratio r∼0.001, wide (a few degrees in diameter), precise (σQ , σU∼ 20 μKCMB arcmin), high angular resolution (<FWHM) reference maps are needed to properly take into account the effects of diffuse polarized emission and avoid significant bias in the calibration.
@article{arxiv.2106.04841,
title = {The Crab Nebula as a Calibrator for wide-beam Cosmic Microwave Background polarization surveys},
author = {Silvia Masi and Paolo de Bernardis and Fabio Columbro and Alessandro Coppolecchia and Giuseppe D'Alessandro and Lorenzo Mele and Alessandro Paiella and Francesco Piacentini},
journal= {arXiv preprint arXiv:2106.04841},
year = {2021}
}