GeV gamma-ray emission in the field of young massive star cluster RCW 38

• DOI: 10.48550/arxiv.2403.19362
• Publication Date: 2024-01-01
• Authors: Ge, Ting-Ting; Sun, Xiao-Na; Yang, Rui-Zhi; Tam, Pak-Hin Thomas; Lu, Ming-Xuan; Liang, En-Wei
• Keywords: High Energy Astrophysical Phenomena (astro-ph.HE); FOS: Physical sciences; Astrophysics - High Energy Astrophysical Phenomena

8 pages, 5 figures, accepted for publication in MNRAS. arXiv admin note: text overlap with arXiv:2210.01352<br/>We report the detection of gamma-ray emission by the Fermi Large Area Telescope (Fermi-LAT) towards the young massive star cluster RCW 38 in the 1-500 GeV photon energy range. We found spatially extended GeV emission towards the direction of RCW 38, which is best modelled by a Gaussian disc of 0.23$°$ radius with a significance of the extension is $\sim 11.4 σ$. Furthermore, the spatial correlation with the ionized and molecular gas content favors the hadronic origin of the gamma-ray emission. The gamma-ray spectrum of RCW 38 has a relatively hard photon index of $2.44 \pm 0.03$, which is similar to other young massive star clusters. We argue that the diffuse GeV gamma-ray emission in this region likely originates from the interaction of accelerated protons in the stellar cluster with the ambient gas.<br/>