The radial distribution in nearby galaxies of the ionizing field of radiation of hii regions using photoionization models

Symposium A30 (Astronomy in Focus XXX) August 2018 , p. 258 presented at IAU XXX General Assembly, Vienna, Austria.-- Published online by Cambridge University Press: 03 March 20Hii regions in galaxy disks can be used as a powerful tool to trace the radial distribution of several of their properties and shed some light on the different relevant processes on galaxy formation and evolution. Among the properties that can be extracted from the study of the ionized gas are the metallicity, the excitation and the hardness of the ionizing field of radiation. In this contribution we focus on the determination of both the ionization parameter (U) and the effective temperature of the ionizing clusters (Ta) by means of a bayesian-like comparison between the observed relative fluxes of several emission-lines with the predictions from a set of photoionization models. We also show the implications that the use of our method has for the study of the radial variation of both U and Ta in some very well-studied disk galaxies of the Local Universe. © International Astronomical Union 2020