\begin{table}%t3
\caption{\label{tab:spectra}Overview of the spectral results for the seven active X-ray transients, obtained from the average outburst spectra.}
\par
\small%\centerline
 {
\begin{tabular}{l l l l l l l l l l}
\hline
\hline
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Source & Year & $N_{{\rm H}}$$^{a}$ & $\Gamma$ & red. $\chi^{2}$ & $F_{{\rm X, abs}}$$^{b}$ & $F_{{\rm X, unabs}}$$^{c}$ & $F_{{\rm X, peak}}$$^{d}$ & $L_{{\rm X}}$$^{e}$ & $L_{{\rm X, peak}}$$^{f}$\\
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\hline 
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AX J1745.6-2901 & 2006 & $23.1 \pm 1.3$ & $2.3 \pm 0.2$ & 1.11 & $14.7^{\rm +0.3}_{-0.2} $ & $50.4^{\rm +4.6}_{-3.8}$ & $120$ & $39$ & $92$ \\
 & 2007 & $24.9^{\rm +0.6}_{-0.7}$ & $2.8 \pm 0.1$ & 1.14 & $ 44.8^{\rm +0.4}_{-0.3}$ & $205^{\rm +9}_{-11}$ & $800$ & $160$ & $610$ \\
CXOGC J174553.5-290124 & 2006 & $14.2^{\rm +5.1}_{-7.4}$ & $1.1^{\rm +1.2}_{-1.1}$ & 1.40 & $ 1.25^{\rm +0.25}_{-0.21}$ & $2.25 ^{\rm +1.10}_{-0.43}$ & $4.0$ & $1.7$ & $3.0$ \\
CXOGC J174540.0-290005 & 2006 & $8.63^{\rm +5.66}_{-5.00}$ & $1.4^{\rm +1.0}_{-0.9}$ & 1.54 & $ 7.81^{\rm +0.92}_{-0.88}$ &  $ 12.5^{\rm +4.9}_{-2.2}$ & $30$ & $9.6$ & $23$ \\
Swift J174553.7-290347 & 2006 & $24.4^{\rm +10.1}_{-7.7}$ & $3.0^{\rm +1.6}_{-1.1}$ & 1.23 & $ 1.53^{\rm +0.22}_{-0.24}$ & $7.73^{\rm +18.0}_{-3.49}$ & $26$ & $5.9$ & $20$ \\
Swift J174622.1-290634 & 2006 & $11.7^{\rm +6.1}_{-3.9}$ & $3.3^{\rm +1.4}_{-1.0}$ & 0.57 & $ 0.468\pm0.064$ & $1.55^{\rm +2.06}_{-0.55}$ & $9.1$ & $1.2$ & $7.0$ \\
GRS 1741.9-2853 & 2006 & $14$ fix & $5.0^{\rm +2.5}_{-2.7}$ & 0.84 & $0.646^{\rm +0.424}_{-0.199}$ & $5.07^{\rm +4.36}_{-2.38}$ & $12$ & $3.9$ & $9.2$ \\
 & 2007 & $14.0^{\rm +1.0}_{-0.9}$ & $2.6 \pm 0.2$ & 1.15 & $61.6\pm1.2$ & $175^{\rm +17}_{-14}$ & $260$ & $130$ & $200$ \\
XMM J174457-2850.3$^{g}$ & 2007 & $6$ fix& $1.3$ fix& & $0.21$ & $0.29$ & $1.4$ & $0.22$ & $1.1$  \\
\hline
\end{tabular}}
\medskip
$^a$ Hydrogen column density in units of $10^{22}~{\rm H~cm}^{-2}$;
$^b$~mean 2$-$10~keV absorbed outburst flux in units of $10^{-12}~{\rm erg~cm}^{-2}~{\rm s}^{-1}$;
$^c$~mean 2$-$10~keV unabsorbed outburst flux in units of $10^{-12}~{\rm erg~cm}^{-2}~{\rm s}^{-1}$;
$^d$~unabsorbed peak flux observed during the outburst in units of $10^{-12}~{\rm erg~cm}^{-2}~{\rm s}^{-1}$;
$^e$~the mean outburst X-ray luminosity, in units of $10^{34}~{\rm erg~s}^{-1}$, is calculated from the mean unabsorbed flux by adopting a distance of 8~kpc for all sources;
$^f$~the peak X-ray luminosity, in units of $10^{34}~{\rm erg~s}^{-1}$, is calculated from the peak unabsorbed flux by adopting a distance of 8 kpc for all sources;
$^g$~fluxes for XMM~J174457-2850.3 were deduced using PIMMS, with $N_{{\rm H}}$ and $\Gamma$ fixed at the values obtained by \citet{sakano05}.
\end{table}