On a method to resolve the nuclear activity in galaxies 7 4. The central intensities of the two superimposed emission disks for each emission line. 5. The position of the last pixel of the jet. 6. The intensities along the jet flow for each emission line. 7. The common velocity and the intensities in the postshock cloud for each emission line. large optical depth, referred to as Case B described in chapter 4.2 of Osterbrock (1989). Accordingly, for an electron temperature of 10000 K, the H α /H β is 2.87, which we note is not much different from the case when the gas is assumed to be optically thin. As evident, the nuclear source and the jet fall in the region of highly excited AGNs, while the inner disk and the postshock cloud fall close to the region of Low Ionization Nuclear Emission line Regions (LINERs). The ratios [NII]/H α places the outer part of the nuclear disk and the spiral arms in the HII region domain. The fit of Model 3 to the velocities and intensities of the various emission lines is displayed in Fig. 7, and the parameters are given in Table 1. The table also con- tains measurements for the spiral arms with the SPLOT routine where they intersect with the present slit. The contribution from the underlying H α and H β ab- sorption lines only change the derived emission line ra- tios marginally. However, the effect of reddening has not been taken into account in the emission ratios presented in Fig. 9 and Table 1. As we have used the unreddened ratio H α /H β , our derived [OIII]/H β ratios presented in the diagram are lower limits in the presence of redden- ing. This is an effect that favours our conclusions about the nature of the components. The nuclear point source shows the highest excitation. If H β would be included in this analysis, its derived true intensity in the Nuclear point source would with H α give the true absorption of the nuclear source of this Seyfert 2 galaxy. Unfortunately, H β is much too faint and uncer- tain to be fitted with our procedure. Stronger exposed H β would be needed. Our best fit, Model 3, gives an observed redshift of the central source of 4100 km s − $^{1}$, or 4089 km s − 1 with heliocentric velocity correction. The total M × sin $^{2}$( i ) of the bulge is determined essentially by the velocities of H α and [NII] at the distance − 6 ′′ from the center. The best fit gives M × sin $^{2}$( i ) = 14 × 10 9 M$_{⊙}$. The remaining parameters of this fit are given in Table 1. Fig. 8 illustrates Table 1 and gives the intensities and velocities of the various features before smearing with the PSF. The central intensities of the emission line disks are essentially given by the run of velocities from − 3 ′′ to − 1 ′′ and from +2 ′′ to +4 ′′ from the center. The position of the shock falls at the border between pixel 5 and 6, i.e. 1 . $^{′′}$5, from the center. This, in turn, forces the postshock velocity up to about +250 km s − $^{1}$in pixels 6 and 7. Figure 7 shows that the velocities and intensities can be reproduced with fair accuracy within this nuclear re- gion. Finally, the diagnostic line ratios log [NII]/H α and log [OIII]/H α , are given in Table 1 for the various com- ponents. The H β intensities are too weak and uncertain to give a unique solution in the present case. The emission line map of Dumas et al. (2007) shows that the maximum intensity for our jet lies in about PA 130 $^{◦}$, and there is also a fainter counter-jet in the op- posite direction. Thus, our slit avoids the maximum in- tensity of the jet and also the counter-jet. As seen from Fig. 7, this means that there is no need for a counter- jet in our model. However, Disk 1 which is completely drowned on he East side by the jet, may in reality corre- spond to a trace of an absorbed counter-jet. Its position fin Fig. 9 does not contradict this. On the other hand, the introduction of a counter-jet in our model would add a number of uncertain intensity parameters. The HST/STIS spectrum (Fig. 4) indicates a high den- sity for the jet, and the jet intensity maps display a bent spiral-like morphology consistent with a precessing jet flow. Considering the angle of about 45 ◦ between the jet axis and our slit, the jet may be surrounded by a more widespread outflow, similar to the one observed in the nu- cleus of the Seyfert 1.5 galaxy NGC 1365 (Hjelm & Lind- blad 1996). Moran et al. (2000) conclude that NGC 1358 belongs to the class of about 50 % Seyfert 2s that do not contain a polarized broad line region (NPBL Sy2). Shu et al. (2007) argue that NPBL Sy2s can be interpreted in the framework of the AGN unified model if the absorp- tion column density is higher at large inclinations and the scattering region is absorbed at large inclinations. Thus, the inclination of the jet to the line of sight may be large and the outflow motion considerably higher than 214 km s − $^{1}$. The emission line disk intensities are completely hid- den behind the strong features in the central part and too faint to be measured at larger distances from the center. They are therefore completely determined by the influ- ence of this disk on the observed total velocities. Disks 1 and 2 represent the inner and outer parts, respectively, of this nuclear emission line disk. Their line ratios then With the emission line fluxes for these structures we are able to set up the Starburst-AGN diagnostic diagrams introduced by Baldwin, Phillips & Terlevich (1981) and Veilleux & Osterbrock (1987). Figure 9 shows the diag- nostic diagram log [OIII]/H β versus log [NII]/H α where the [OIII]/H β ratio is derived from [OIII]/H α assuming Our “best fit” Model 3 resolves the nuclear structure of NGC 1358 into 6. DISCUSSION 4) an emission line region, the postshock cloud, at the end of the jet, and after a drastic jump in velocity. 3) a spherical nuclear stellar bulge containing a rotat- ing emission line disk, inclined to the stellar kine- matic symmetry plane of the bulge, 2) a 1 . $^{′′}$5 long jet emerging from the nucleus with a line of sight velocity of − 214 km s − $^{1}$, 1) a central unresolved emission line source (the Nu- cleus), 5. RESULTS