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arXiv · 2403.19362

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

Ting-Ting Ge·Xiao-Na Sun·Rui-Zhi Yang·Pak-Hin Thomas Tam·Ming-Xuan Lu·En-Wei Liang
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Abstract

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$\deg$ radius with a significance of the extension is $\sim 11.4 \sigma$. 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.

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Ting-Ting Ge, Xiao-Na Sun, Rui-Zhi Yang, Pak-Hin Thomas Tam, Ming-Xuan Lu, En-Wei Liang. 2024-03-28. GeV gamma-ray emission in the field of young massive star cluster RCW 38. https://arxiv.org/abs/2403.19362

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