Table 1: Mean spectral properties from the stacking analysis of sources in the 3 $\sigma$ hard sample detected in the pn at off-axis angle <11 $^\prime$ . $N_{\rm H}$ is fixed to the galactic value.
Flux bins N. of sources $\Gamma$

$-14.1 < \mbox{log}~F_{\rm X} < -13.7$ 25 $\rm 1.72^{+0.09}_{-0.09}$

$-13.7 < \mbox{log}~F_{\rm X} < -13.6$ 22 $\rm 1.81^{+0.09}_{-0.08}$

$-13.6 < \mbox{log}~F_{\rm X} < -13.5$ 15 $\rm 1.83^{+0.10}_{-0.09}$

$-13.5 < \mbox{log}~F_{\rm X} < -13.3$ 14 $\rm 1.76^{+0.08}_{-0.08}$

$-13.3 < \mbox{log}~F_{\rm X} < -12.9$ 7 $\rm 1.75^{+0.12}_{-0.12}$

**Table 1:** Mean spectral properties from the stacking analysis of sources in the 3 $\sigma$ hard sample detected in the pn at off-axis angle <11 $^\prime$ . $N_{\rm H}$ is fixed to the galactic value.
Flux bins	N. of sources	$\Gamma$
$-14.1 < \mbox{log}~F_{\rm X} < -13.7$	25	$\rm 1.72^{+0.09}_{-0.09}$
$-13.7 < \mbox{log}~F_{\rm X} < -13.6$	22	$\rm 1.81^{+0.09}_{-0.08}$
$-13.6 < \mbox{log}~F_{\rm X} < -13.5$	15	$\rm 1.83^{+0.10}_{-0.09}$
$-13.5 < \mbox{log}~F_{\rm X} < -13.3$	14	$\rm 1.76^{+0.08}_{-0.08}$
$-13.3 < \mbox{log}~F_{\rm X} < -12.9$	7	$\rm 1.75^{+0.12}_{-0.12}$

Source LaTeX | All tables | In the text