created by weighting the published matrices for each response validity period according to the photon fluence from the source during that validity period. This method takes into account both the different exposure in each validity period, and any source variability present. A single rmf response is used, corresponding to the standard rmf, rebinned according to the 14 channels used for spectral analysis. For [NGC 4388]{}, the spectrum was derived from 4770 pointings with a total on-source time (not adjusted for off-axis response) of 7.5 Ms. The corresponding figures for [NGC 2110]{} are 2249 pointings for 3.8 Ms total on-source time. In both cases, the observations are spread reasonably uniformly across the time period analysed.

                  $\sigma_{100-120}$   $\sigma_{120-150}$   $\sigma_{150-300}$
  -------------- -------------------- -------------------- --------------------
   [NGC 4388]{}          22.2                 17.6                 8.6
   [NGC 2110]{}          17.6                 12.9                 6.6

  : IBIS source significance of [NGC 4388]{} and [NGC 2110]{} in three energy bands: 100–120 keV, 120–150 keV, 150–300 keV.[]{data-label="tab:src"}

[c c c c c]{} Satellite & Obs. Id. & Start time (<span style="font-variant:small-caps;">utc</span>) & Net exp. & label\
&&yyyy-mm-dd&(ks) &\
\
[[*XMM–Newton*]{}]{}& 0110930301 & 2002-07-07 & 3.8 & XMM1\
[[*XMM–Newton*]{}]{}& 0110930701 & 2002-12-12 & 7.3 & XMM2\
[[*XMM–Newton*]{}]{}& 0675140101 & 2011-06-18 & 37.7& XMM3\
[[*NuSTAR*]{}]{}& 60061228002 & 2013-12-27 