\begin{table}%t3
%\centering
\par
\caption{The instrumental calibration parameters from the APEC model fit
 simultaneously to the \mbox{XIS-0}, 1, 2, and 3.}\label{tab3}
\small \begin{tabular}{llll}
\hline\hline \noalign{\smallskip}
Sensor & Relative normalization & $N_{\rm c}~\left[10^{18}{\rm cm^{-2}}\right]$ & Gain offset [eV] \\
\hline
XIS-0  & 1(Fix)  & $0.012({<} 0.116)$     & $-12.0$ ($-20.0$--$-6.0$) \\
XIS-1  & 1.035(1.023--1.047)  &  0.093(0.014--0.184) & $-16.0$ ($-22.5$--$-10.2$) \\
XIS-2  & 1.019(1.007--1.030)  &  0.011(${<}0.116$)     & $-9.8$ ($-16.5$--$-3.1$) \\
XIS-3  & 1.049(1.038--1.060)  &  0.000(${<}0.100$)     & $-20.1$ ($-26.4$--$-14.2$) \\
\hline
\end{tabular}
\end{table}