\begin{table}%t2
\caption{\label{t:BAT_XRT_spec}Best-fit model parameters of the 15--150~keV and of the 0.3--10~keV spectra of the $\gamma$-ray prompt and \mbox{X-ray} afterglow measured with BAT and XRT, respectively$^{a}$.}
%\centerline
 {\small \begin{tabular}{lcrrccccc}
\hline  \hline
\noalign{\smallskip}
Interval  & Energy band & Start time  & Stop time  & $\beta$ & $N_{\rm H,z}$    & Mean flux & $A_{V,z}^{b}$ & $\chi^2$/d.o.f.\\
& (keV)       & (s)         & (s)        &          & ($10^{21}$~cm$^{-2}$) & (erg~cm$^{-2}$~s$^{-1}$) & &  \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
$T_{90}$      &  15--150 &   $0.0$  &   $67.0$ & $1.44\pm0.46$    &  --  & $(3.3\pm0.8)\times10^{-7}$ &  --  & $1.44/6$ \\
Total         &  15--150 &  $-2.0$  &   $90.0$ & $1.65\pm0.51$    &  --  & $(3.6\pm0.8)\times10^{-7}$ &  --  & $5.6/7$  \\
Pulses 1--3   &  15--150 &  $-2.0$  &   $20.0$ & $2.0\pm0.5$      &  --  & $(2.2\pm0.5)\times10^{-7}$ &  --  & $1.82/7$ \\
Pulse 4       &  15--150 &  $52.9$  &   $90.0$ & $1.4\pm0.5$      &  --  & $(1.4\pm0.5)\times10^{-7}$ &  --  & $5.8/5$  \\
Peak          &  15--150 &  $0.384$ &   $0.832$& $1.1\pm0.6$      &  --  & $(1.0\pm0.2)^{c}$          &  --  & $6.1/6$  \\
%\hline
XRT-WT  &  0.3--10 &  $77$  & $134$  & $\rm 1.06_{-0.09}^{+0.10}$&$<$1.4& $(4.1\pm0.3)\times10^{-10}$  & -- & $28.3/31$ \\[1mm]
Plateau &  0.3--10 &  $423$ & $1507$ & $\rm 0.80_{-0.15}^{+0.16}$ & $\rm 1.6_{-1.5}^{+1.8}$ & $(2.3\pm0.3)\times10^{-11}$ & -- & $17.2/24$ \\
%\hline
SED~2 &  opt-X  & $186.8$ & $269.4$  & $0.74\pm0.03$& $[2.7]$ & -- & $<$0.04 & $8.2/6$ \\
SED~3      &  opt--X  & $423$   & $1507$   & $0.79\pm0.01$ & $2.7\pm0.8$ & -- & $< $0.02 & $32/34$ \\
SED~4      &  opt     & 78~117 & 93~620 & $0.85\pm0.30$ & -- & -- & $0.10_{-0.06}^{+0.14}$ & $3.4/4$ \\[1mm]
%\hline
SED~2      &  opt     & $186.8$ & $269.4$  & $0.61\pm0.13$ & --  & -- & $[0]$ & $3.1/3$ \\
SED~3      &  opt     & $423$   & $1507$   & $0.74\pm0.05$ & --  & -- & $[0]$ & $7.9/8$ \\
SED~4      &  opt     & 78~117 & 93~620  & $1.05\pm0.06$ & --  & -- & $[0]$ & $4.8/5$ \\
 \hline
 \end{tabular}}
\medskip
$^{a}$ The model is an absorbed power law ({\tt xspec} model: {\tt pegpwrlw} for BAT and {\tt wabs} {\tt pow} for XRT data, respectively). Frozen values are reported among square brackets. SED modelling results are also reported, both derived for the broad band from optical to \mbox{X-ray}s and optical points alone. The extinction is modelled with a SMC profile as parametrised by \citet{Pei92}; $^{b}$~rest-frame extinction obtained by modelling the SED with an SMC profile as parametrised by \citet{Pei92}; $^{c}$~peak photon flux in units of ph~cm$^{-2}$~s$^{-1}$.
\end{table}