3D spectroscopy of giant HII regions in nearby spiral galaxies
Integral field spectroscopy (IFS) allow to simultaneously record spectral and spatial information over the observed area. Taking advantage of this capability a program was started to search for possible variations of physical parameters inside star forming regions. The ideal candidates are HII regions in face-on nearby spiral galaxies, allowing also to study the differences in the star formation process in the centre vs. the outer disc environments.
In this talk I will present IFS observations of HII regions in M33 and M101, their physical properties (density, temperatures, ionic and total abundances, etc.) were derived at different scales, from individual spatial resolution elements (spaxels) to the whole integrated field. Multiscale results and comparison with literature show the limitation of the methodologies developed for global observations (long slit, single aperture) when used with spatially resolved data. In this case the ionization structure within the nebula must be taken into account and
a different interpretation of the results is required. BPT diagnostic diagrams where used to characterize the contribution of different parts of the nebula to the global result, also to test photoionization models with a simple approach to include spatial information.