Melekh B. Modelling of the nebular environments radiation

The research results of the various nebular environments using both the grid and optimization methods as well as the multicomponent ones are represented. In each of the proposed approaches and methods the comparison of the modelling results with observed data was done. Using grid photoionization modelling (PhM) of the nebular environments it was shown that ONS-calibrations for oxygen abundance determination are more reliable than ON ones.The influence of the various kinds of dust grains on the planetary nebulae (PNe) spectra was investigated in details, and correspondence of the PNe PhM results to the observed photometrical data in IR-wavelength region was checked. It was also investigated the impact of dust grains presence in PN envelope on determination of its chemical compositions. The iterative-optimization method as well as two-three stages of the optimized PhM (OPhM) ones were developed for the various nebular environments. The suggested methods are used to determine the OPhM of HII regions, PNe and supernova remnant. On the base of the three-stages OPhM approach the method to determine the distance and mass of the planetary nebula envelope was developed and tested. The multicomponent PhM (MPhM) method was developed to take into account the presence of the superwind bubble. Also the multisector MPhM method was developed for photoionization analysis of chemodynamical dwarf galaxies simulations (ChDSs). This method was used to test the relation between stars formation rate and luminosity in H-alpha emission line as well as for estimating of the fraction of the ionizing quanta escaping out the galaxy. It was concluded that thin dense shell(s) (in comparison with ChDSs results) should be present in dwarf galaxies to reproduce by models the observed intensities of low-ionization emission lines.