Extension studies of galactic sources with Fermi

Abstract

The Fermi data analysis tools have been developed on maximum likelihood minimization routine. This analysis technique is extensively used to determine the spectral parameters as the flux and the spectral index of a gamma-ray source, crucial aspects in determining how particles are accelerated, but it may also be used to measure the extension of not pointlike emission regions obtaining precious information about the sites where the acceleration takes place. The capability of the analysis presented here has been deeply studied with simulations varying the source flux, the spectral index, and the position within the galactic plane. This analysis procedure has been applied for determining the extension of the Vela X [1] and the MS H 1552 [2] [3] PWNe, as well as the extension of the W51C [4], W44 [5] and the IC443 [6] SNRs.