integrated the fluxes over a circular aperture of diameter 30$^{\prime\prime}$ to encompass all the emission. The line intensities are listed in Table \[table:lines\]. Observations of the \[O [iii]{}\], \[C [ii]{}\], and \[O [i]{}\] 63 and 145 $\mu$m lines were also performed with the LWS instrument onboard [*ISO*]{} [@bergvall-2000; @brauher-2008; @vasta-2010]. The PACS intensities of the \[O [i]{}\] 63 $\mu$m and \[O [iii]{}\] lines agree within 40% with the LWS observations, although they are found to be lower with PACS. This may be attributed to a beam effect, the LWS beam size being $\sim$80$^{\prime\prime}$. However, we find that the \[C [ii]{}\] intensity is two times brighter with PACS compared to LWS. To understand this discrepancy, we have reduced the PACS data with different flat-field corrections, as well as with background normalization (PACS Data Reduction Guide). All these methods give the same final \[C [ii]{}\] flux as quoted in Table \[table:lines\] within 10%, ruling out a mis-calibration from PACS. Therefore we attribute the difference between the PACS and LWS fluxes to a calibration problem from the LWS instrument.

  ---------------------------- -------- ----------- ------- ------- ------- ------------------------------------------------------------
                                                                            
                                                                            
  [*Spitzer*]{}/IRS                                                         
  $\rm{[}$S [iv]{}$\rm{]}$      10.51      5.37      0.66    34.79   1 369                  5 $\times \rm{10^{4}}$ \[e\]
  $\rm{[}$Ne [ii]{}$\rm{]}$     12.81      3.53      