Open Access
This article is an erratum for:

Volume 664, August 2022
Article Number C1
Number of page(s) 2
Section Astronomical instrumentation
Published online 18 August 2022

A computational error has been found in the formula used to convert polarization angle values from equatorial to Galactic coordinates as reported in Table 2 of our original article. This concerns only ψgal values in parenthesis, regarding the NIKA camera observations. An updated version of Table 2 is given in Table 1 with new values having been recomputed. The bottom panel of Fig. 6 of the original article has been updated accordingly (see Fig. 1). This correction, however, does not significantly affect the result of the weighted-average polarization angle, which is now equal to −87.8° instead of −87.7°, which is consistent within the uncertainty previously given. It is important to notice that the uncertainties associated with the polarization angle values are not affected by the coordinate change correction.


We thank Ricardo T. Génova-Santos for the discussions that led to find this error.

© A. Ritacco et al. 2022

Licence Creative CommonsOpen Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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All Tables

Table 1

NIKA Crab nebula total flux I, Q, and U are presented here and were estimated by using aperture photometry methods.

All Figures

thumbnail Fig. 1

Top: polarization degree as a function of frequency as measured by Planck (black dots), WMAP (blue triangles), XPOL (yellow diamond), POLKA (green cross), and NIKA (red crosses). The NIKA and POLKA values have been estimated by aperture photometry considering the source extension up to 9′. Planck and WMAP values are shown at their native resolution. XPOL, NIKA, and POLKA values have been integrated over the source. The solid line represents the weighted-average degree for all experiments but POLKA. Dashed lines represent 1σ uncertainties. Bottom: polarization angles in Galactic coordinates for the same five experiments. The solid line represents the weighted-average polarization angle computed using all the values.

In the text

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