\begin{table}%t1
\caption{List of symbols.}
%\begin{center}
\par
\begin{tabular}{lp{0.75\hsize}}
\hline\hline
Symbol & Description\\
\hline
$\chi$ & Polarization angle (N through E)\\
 $\chi_0$& Polarization angle at $\lambda = 0$\\
$\nu$  & Frequency\\
 $\delta\nu$ & Channel width in frequency\\
$\nu_{\rm c}$ & Central frequency of a channel\\
 $\lambda$ & Wavelength\\
$\lambda_0$ & Wavelength to which all polarization vectors are
derotated\\
$\lambda_{\rm c}^2$& Central wavelength squared of a channel\\
$\delta\lambda^2$ & Channel width in wavelength squared\\
$\Delta\lambda^2$ & Total bandwidth in wavelength squared.
$\Delta\lambda^2 = \lambda^2_{\rm max} - \lambda^2_{\rm min}$\\
$\phi$ & Faraday depth\\
$\delta\phi$ & FWHM of the main peak of the RMTF\\
$\mbox{RM}$ & Rotation measure\\
$W(\lambda^2)$ & Weight function\\
$w_i$ & Weight of the $i$th data point\\
$K$ & One over the integral of $W$ or one over the sum of weights\\
$F(\phi)$ & Faraday dispersion function without spectral dependence\\
$\tilde{F}(\phi)$ & Reconstructed approximation to $F(\phi)$\\
$F(\phi, \lambda^2)$ & General form of the Faraday dispersion function\\
$f(\phi)$ & $F(\phi,\lambda^2)/s(\lambda^2)$\\
$s(\lambda^2)$ & Spectral dependence in $I$, normalized to unity at
$\lambda^2 = \lambda^2_0$\\ 
$\alpha$ & Frequency spectral index\\
$P(\lambda^2)$ & Complex polarized surface brightness\\
$\tilde{P}(\lambda^2)$ & Observed $P$: $W(\lambda^2)P(\lambda^2)$\\  
$p(\lambda^2)$ & Complex polarization fraction
$P(\lambda^2)/I(\lambda^2)$\\
$R(\phi)$ & Rotation Measure Transfer Function (RMTF)\\
$\vec{B}$ & Magnetic induction\\
$\vec{r}$ & Position vector\\
$n_{\rm e}$& Thermal electron density\\
$\gamma$ & Spectral index of the relativistic electron energy distribution\\
$\Re z$ & Real part of $z$\\
$\Im z$ & Imaginary part of $z$\\
$\rho$ & Merit function for traditional linear least squares fitting of rotation measures. Defined in Eq.~(\ref{brentjens_eqn:rho})\\
$\sigma$ & rms noise in a single channel map\\
$\sigma_{\rm Q}$, $\sigma_{\rm U}$ & rms noise in single $Q$ or
$U$ channel maps\\
$\sigma_{\rm P}$, $\sigma_\chi$ & Standard error
of $\|P\|$ and $\chi$ in individual channel maps\\
$\sigma_\phi$, $\sigma_{\chi_0}$ & Standard error in Faraday depth
and position angle at $\lambda=0$\\
$\sigma_{\lambda^2}$ & Standard deviation of the distribution of
$\lambda^2$ values that are sampled. This is a measure of the
effective width of the $\lambda^2$ sampling\\
$\delta(x)$ & Dirac delta function\\
\hline
\end{tabular}
%\end{center}
\par
\label{brentjens_tab:list_of_symbols}
\end{table}