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arXiv · 1603.02358

Detection of gamma-ray emission from globular clusters M 15, NGC 6397, NGC 5904, NGC 6218 and NGC 6139 with Fermi-LAT

P. F. Zhang·Y. L. Xin·L. Fu·J. N. Zhou·J. Z. Yan·Q. Z. Liu·L. Zhang
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Abstract

In the third Fermi catalogue (3FGL) there are sixteen gamma-ray globular clusters. After analyzing the recent released Pass 8 data of Fermi Large Area Telescope (LAT), we report the discovery of significant gamma-ray emission from M 15 and NGC 6397, confirm that NGC 5904 is a gamma-ray emitter and find evidence of gamma-ray emission from NGC 6218 and NGC 6139. Inter- estingly, in the globular clusters M 15, NGC 6397 and NGC 5904, millisecond pulsars (MSPs) have been found in radio or X-rays, which are strongly in support of the MSP origin of the gamma-ray emission. However, due to the relative low luminosity of the gamma-ray emission we do not find any evidence for the gamma-ray pulsation or flux variability of these sources.

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P. F. Zhang, Y. L. Xin, L. Fu, J. N. Zhou, J. Z. Yan, Q. Z. Liu, L. Zhang. 2016-03-08. Detection of gamma-ray emission from globular clusters M 15, NGC 6397, NGC 5904, NGC 6218 and NGC 6139 with Fermi-LAT. https://doi.org/10.1093/mnras/stw567

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