Photometry of 119 HII regions in M33

We obtain the spectral energy distribution (SED) from the UV (GALEX) to the far IR (Herschel) performing photometry in each HII region of the sample. We model the SED using DustEM tool to understand the dust evolution in different environments.

The fraction of very small grains can be affected by the conditions of the interstellar environment: strong shocks existing in the interior of the most luminous HII regions can lead to fragmentation of big grains into smaller ones, while the more evolved objects provide a more quiescent environment where reformation of dust big grains might occur.