Morphological and spectral study of 4FGL J1115.1-6118 in the region of the young massive stellar cluster NGC 3603

Abstract

We report a detailed study of an unidentified gamma-ray source located in the region of the compact stellar cluster NGC 3603. This is a star-forming region (SFR) powered by a massive cluster of OB stars. A dedicated analysis of about 10 years of data from 10 GeV - 1 TeV, provided by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope, yields the detection of a pointlike source at a significance of 9$\sigma$. The source photon spectrum can be described by a power-law model with best fit spectral index of $2.35\pm 0.03$. In addition, the analysis of a deep Chandra image in the 0.5 - 7 keV band reliably rules out an extragalactic origin for the gamma rays. We also conclude that the broadband spectral energy distribution of the point source can be explained well with both leptonic and hadronic models. No firm evidence of association with any other classes of known gamma-ray emitters is found, therefore we speculate that 4FGL J1115.1-6118 is a gamma-ray emitting SFR.

arXiv comment16 pages, 9 figures, 7 tables. Submitted to ApJ

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• Multi-messenger-Athena Synergy White Paper
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• Machine learning methods for constructing probabilistic Fermi-LAT catalogs
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• High energy cosmic rays and gamma rays from star clusters: the case of Cygnus OB2
• A Multiwavelength Machine-learning Approach to Classifying X-ray Sources in the Fields of Unidentified 4FGL-DR4 sources
• Probing the star formation origin of gamma rays from 3FHL J1907.0+0713
• Exploring non-thermal emission from the star-forming region NGC 3603 through a realistic modelling of its environment
• Direct simulations of very high energy cosmic ray acceleration in 3D MHD model of a compact star cluster