Star-forming regions have been proposed as potential Galactic cosmic-ray accelerators for decades.
Cosmic ray acceleration can be probed through observations of gamma-rays produced in inelastic
proton-proton collisions, at GeV and TeV energies. We analyze more than 11 years of Fermi-LAT
data from the direction of Westerlund 2, one of the most massive and best-studied star-forming
regions in our Galaxy. The spectral and morphological characteristics of the LAT source agree
with the ones in the TeV regime (HESS J1023-575), allowing the description of the gamma-ray
source from a few hundreds of MeV to a few tens of TeVs. We will present the results and discuss
the implications of the identification with the stellar cluster and the radiation mechanism involved.