Marco Sirianni

The scientific part of my Thesis (STScI/ CISAS - University of Padova) is concentrated on a study of star formation in starburst galaxies. High-mass star formation regions in the Local Group of galaxies are excellent laboratories to study starbust: their proximity permits detailed studies of individual star. In this context I worked in the past on NGC1569: deep WFPC2 imaging allowed us to resolve stars down to 4M$_{\odot}$ and to derive th SF history over the last 0.15 Gyr. I am currently working on R136, the dominant cluster of 30 Dor; we used all the available WFPC2 archive observations to derive the IMF down to 1.4M$_{\odot}$:we find for the first time a clear flattening of the IMF slope for mass lower than 3M$_{\odot}$ and set an upper lower mass limit to 1 M$_{\odot}$.