Notes. Column 1 gives the RM source number, as in Savage et al. (2013); Cols. 2 and 3 list the Galactic coordinates of the source; Col. 4 gives the linear distance from the centre of the Rosette; Col. 5 lists the mean electron density estimated with Eq. (5) for f = 1; Col. 6 gives the RM data corrected for the background contribution; and the last column gives the line-of-sight component of the magnetic field estimated with Eq. (6) for f = 1. The uncertainties in both ⟨ n_e ⟩ and B_|| are statistical, and thus do not include the systematic uncertainties involved, namely those on the distance to the Rosette, its electron temperature, path length (which depends on the radii), electron density distribution, and the calibration uncertainty of the EM data.