Erratum to: Magnetic fields in spiral galaxies

1 Erratum to: Astron Astrophys Rev (2016) 24:4 DOI 10.1007/s00159-015-0084-4

Due to a rounding error, the constant in all equations involving Faraday rotation measures is incorrect. Equation (10) should read:

$$\begin{aligned} \chi = \chi _0+\varPhi \,\lambda ^2,\quad {\mathrm {where}}\,\,\, \varPhi = 0.812 \int \limits _{\mathrm{source}}^{\mathrm{observer}} B_{{\mathrm {reg}},\parallel } \, n_{\mathrm {e}}\,\mathrm{d}l \end{aligned}$$

Equation (11) should read:

$$\begin{aligned} \hbox {RM/DM} = 0.812 \langle B_{{\mathrm {reg}},\parallel } \, n_{\mathrm {e}} \rangle /\langle n_{\mathrm {e} }\rangle \end{aligned}$$

Equation (15) should read:

$$\begin{aligned} \sigma _{{\mathrm {RM}}} = 0.812 \, B_{{\mathrm {iso}},\parallel } \, \langle n_{\mathrm {e}}\rangle \, \sqrt{Ld/f} \end{aligned}$$

Furthermore, one term is missing in Eq. (14) that should read:

$$\begin{aligned} p=p_0 \exp (-S) \end{aligned}$$