\begin{table}%t4
\caption{\label{tabella4}The values of the radio spectral index~$\alpha_{\rm r}$, the peak frequency~$\nu_{\rm s}$, the corresponding $\nu_{\rm s}~S(\nu_{\rm s})$ in $10^{-12}$~erg~cm$^{-2}$~s$^{-1}$ and the curvature parameter~$b$ characterising VLBL~candidates.
}
%\centering
\par
\begin{tabular}{crrccrcccc}
\hline\hline\noalign{\smallskip}
         &             &             &  Faint state     &        &             &            &     High state   &      &               \\
 Source  & $\alpha_{\rm r}$~ & Log $\nu_{\rm s}$ & $\nu_{\rm s}~S(\nu_{\rm s})$ &  $b$   & $\alpha_{\rm r}$  & Log $\nu_{\rm s}$ & $\nu_{\rm s}~S(\nu_{\rm s})$ & $b$  & $\Gamma$   \\
\hline                                                                                               \a       &  $-$0.60    & 13.13       &  3.21           & 0.17   & $-$0.60     &  13.02      &  10.7            & 0.20 & 1.74 $\pm$ 0.15 \\
\b       &  $-$0.29    & 13.15       &  3.93           & 0.21   & $-$0.06     &  12.75      &  9.68            & 0.19 & 1.42 $\pm$ 0.11 \\ 
\c       &     0.42    & 12.89       &  1.18           & 0.16   &    0.36     &  12.88      &  2.35            & 0.17 & 1.80 $\pm$ 0.34 \\
\d       &     0.11    & 12.89       &  2.61           & 0.25   &    0.02     &  13.06      &  12.5            & 0.23 &               \\ 
\e       &  $-$0.34    & 12.81       &  7.55           & 0.30   & $-$0.61     &  12.93      &  28.3            & 0.32 &               \\
\f       &     0.11    & 12.97       &  2.58           & 0.20   &    --        &    --        &    --             &   --  &               \\
BZB~J1927+6117       &  $-$0.17    & 12.79       &  8.52           & 0.28   &    --        &    --        &    --             &   --  &               \\
\l       &     0.07    & 13.10       &  1.06           & 0.12   &    0.07     &  12.99      &  2.57            & 0.15 & 1.96 $\pm$ 0.33 \\
\hline
\end{tabular}
\tablefoot {Faint and high state are distinguished. Where available, the values of the photon index~$\Gamma$ of a power~law fit to \sw X-ray data are~reported.}
\end{table}