\begin{table}%t2
%\centering
\par
\caption{\label{expos}Performed and useful exposure times for all {\it XMM-Newton} instruments. The useful RGS exposure time is considerably reduced due to a strong flare of soft protons. The fourth column yields the background-corrected count rate for the source, between 0.4 and 10~keV for EPIC, and between 0.3 and 2.5~keV for RGS. In the case of the RGS instruments, only exposure 0001730201 is considered. The error bars on the count rate represent the $\pm$1~$\sigma$ standard deviation.}
\begin{tabular}{cccc}
\hline\hline
Instrument	& Performed & Effective & Background-corrected \\
	& duration & exposure & count rate \\
	& (s) & (s) & (count~s$^{-1}$) \\
\hline
MOS1 & 25~901 & 25~435 & 0.512 $\pm$ 0.005 \\
MOS2 & 25~906 & 25~473 & 0.532 $\pm$ 0.005 \\
pn & 22~759 & 20~402 & 1.303 $\pm$ 0.009 \\
RGS1 & 16~495 & 7490 & 0.085 $\pm$ 0.006 \\
RGS2 & 16~535 & 6838 & 0.101 $\pm$ 0.006 \\
\hline
\end{tabular}
\end{table}