Mid-infrared Infrared Space Observatory Spectroscopy of the prototypical liner NGC 1052:: shocks reconsidered

We have observed the prototypical LINER NGC 1052 with the Infrared Space Observatory Short-Wavelength Spectrometer. While we have detected the [Ne II] 12.8 mu m line, we have obtained a strict upper limit for the [Ne III] 15.6 mu m line. A large [Ne II]/[Ne III] line ratio and small [Ne III]/[O III] lambda 5007 and [Ne II]/[OIII] line ratios are consistent with slow-shock models with similar to 130 km s(-1) shock velocity. Our results support the original suggestions of shock excitation as a dominant source for NGC 1052. We have fitted the infrared and optical line ratios with a combination of shock and photoionization models. The best combination among the simple models we considered suggests that the contribution of shock and photoionization to [O III] lambda 5007 emission is four-fifths and one-fifth, respectively.