\begin{table}%T1
\caption{Model parameters for the 1997 April flare of Mkn~501.}
\label{t1}
%\centerline
{
\begin{tabular}{lccccccccc@{ }cc}
\hline\hline
Date & $s$ & $r$ & $N$ & $\gamma_0$ & $\gamma_{\rm p}$ & $ V $ &
$E_{\rm e}$ & $\nu L_\nu (SR)$ & $\nu L_\nu (IC)$ & $B$  & $\delta$  \\
     &     &     & cm$^{-3}$ & 10$^4$& 10$^5$& cm$^3$&  10$^{44}$ erg &10$^{39}$erg/s &
10$^{39}$erg/s & G  &   \\
\hline
SSC - 1 zone  &   &     &      &    &  &    &    &     &    \\
Apr. 07 & 1.12 & 0.81 & 4.25 & 4.80 &1.67&
$1.57\times10^{47}$& 91.0 & 8.70&4.47& 0.10 &15  \\
Apr. 16 & 1.18 & 0.70 & 30.0 & 8.70 &3.36   &
$1.72\times10^{46}$& 90.6 & 34.60 & 21.4 &0.14&15  \\ 
%& & & & & & & & & & & &\\
\hline
SSC - 2 zones  &   &     &   &    &    &     &    &     & & &    \\
Apr. 07 (Z1) & 1.14 & 0.81 & 4.6 & 4.0 & 1.35 & 1.2 $\times$ 10$^{47}$ & 57.9 & 8.71 & 3.42 & 0.14 & 15  \\
Apr. 11 (Z2) & 1.2 & 1.00 & 1050 & 14 &3.52&9.2 $\times$ 10$^{40}$ & 0.156 & 6.92& 1.44&1.5&15\\
Apr. 16 (Z2) & 1.2 & 1.33 & 250  & 20 &3.95&9.2 $\times$ 10$^{43}$& 6.12 & 29.5& 14.1 &0.2&15\\ 
\hline
\end{tabular}}
\medskip
$V$ is the volume of the emitting region; $E_{\rm e}$ is the total energy of radiating electrons;
$\nu L_\nu (SR, IC)$ are the SED peak values of SR and IC~components, respectively.
\end{table}