We report the results of our analysis of the publicly available data obtained by the Large Area Telescope ( LAT ) on board of the Fermi satellite towards the direction of the young massive star cluster Westerlund 2 .
We found significant extended \gamma -ray emission in the vicinity of Westerlund 2 with a hard power-law energy spectrum extending from 1 GeV to 250 GeV with a photon index of 2.0 \pm 0.1 .
We argue that amongst several alternatives , the luminous stars in Westerlund 2 are likely sites of acceleration of particles responsible for the diffuse \gamma -ray emission of the surrounding interstellar medium .
In particular , the young star cluster Westerlund 2 can provide sufficient non-thermal energy to account for the gamma-ray emission .
In this scenario , since the \gamma -ray production region is significantly larger than the area occupied by the star cluster , we conclude that the \gamma -ray production is caused by hadronic interactions of the accelerated protons and nuclei with the ambient gas .
In that case , the total energy budget in relativistic particles is estimated of the order of 10 ^ { 50 } ~ { } erg .