\begin{table}%t1
%\centering
\par
\caption{Observational and model parameters (see Sects.~2.1--2.3 for detailed descriptions).}\label{t:1}
\small\begin{tabular}{lll}
\hline\hline
       & Symbol & Dimension\\
\hline
Observational      & $z$  & [dimensionless]\\
parameters         & $D$  & [kpc]\\
derived            & $AR$ & [dimensionless]\\
from radio maps    & $\nu$& [MHz]\\
and spectrum       & $P_{\nu}$& [W~Hz$^{-1}$sr$^{-1}$]\\
\hline
Model free         & $a_{0}$& [kpc]\\
parameters         & $\beta$& [dimensionless]\\
(to be fixed)      & $p=2\alpha_{\rm inj}$+1 & [dimensionless]\\
                   & $\gamma_{\rm i,min}$, $\gamma_{\rm i,max}$ &  [dimensionless]\\
                   & $\Gamma_{\rm c}$, $\Gamma_{\rm x}$ & [dimensionless]\\
                   & $\zeta$ & [dimensionless]\\
                   & $t$    & [yr]\\
                   & $\theta$ & [deg]\\
\hline
Model parameters   & $Q_{\rm jet}$ & [W]\\
derived for given  & $\rho_{0}$ & [kg~m$^{-3}$]\\
values of $t$,     & $p_{\rm c}$& [N~m$^{-2}$]\\
$\alpha_{\rm inj}$ and $\gamma_{\rm i,max}$  &$u_{\rm c}$ & [J~m$^{-3}$]\\
                   & $E_{\rm tot}$ & [J]\\
\hline
\end{tabular}
\end{table}