We report the Fermi Large Area Telescope ( Fermi -LAT ) detection of the \gamma -ray emission towards the young massive star cluster RSGC 1 .
Using the latest source catalog and diffuse background models , we found that the diffuse \gamma -ray emission in this region can be resolved into three different components .
The GeV \gamma -ray emission from the region HESS J1837-069 has a photon index of 1.83 \pm 0.08 .
Combining with the HESS and MAGIC data , we argue that the \gamma -ray emission in this region likely originate from a pulsar wind nebula ( PWN ) .
The \gamma -ray emission from the northwest part ( region A ) can be modelled by an ellipse with the semimajor and semiminor axis of 0.5 ^ { \circ } and 0.25 ^ { \circ } , respectively .
The GeV emission has a hard spectrum with a photon index of 2.05 \pm 0.02 and is partially coincide with the TeV source MAGIC J1835-069 .
The possible origin of the \gamma -ray emission in this region is the interaction of the cosmic rays ( CRs ) accelerated by SNR G24.7+0.6 or/and the OB cluster G25.18+0.26 with the surrounding gas clouds .
The GeV \gamma -ray emission from the southeast region ( region B ) can be modeled as an ellipse with the semimajor and semiminor axis of 0.9 ^ { \circ } and 0.5 ^ { \circ } , respectively , and also reveals a hard \gamma -ray spectrum .
We argue that the most probable origin is the interaction of the accelerated protons in the young massive star cluster RSGC 1 with ambient gas clouds , and the total cosmic-ray ( CR ) proton energy is estimated to be as high as \sim 1 \times 10 ^ { 50 } erg .