| Autor: |
Chen, Xiao-Bin, Wang, Kai, Huang, Yi-Yun, Zhang, Hai-Ming, Xi, Shao-Qiang, Liu, Ruo-Yu, Wang, Xiang-Yu |
| Rok vydání: |
2024 |
| Předmět: |
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| Druh dokumentu: |
Working Paper |
| Popis: |
The supersonic flow motions associated with infall of baryonic gas toward sheets and filaments, as well as cluster mergers, produces large-scale shock waves. The shocks associated with galaxy clusters can be classified mainly into two categories: internal shocks appear in the hot intracluster medium within the viral radius, and external accretion shocks form in the outer cold region well outside of the virial radius. Cosmic-ray (CR) electrons and/or protons accelerated by these shocks are expected to produce gamma-rays through inverse-Compton scatterings (ICS) or inelastic $pp$ collisions respectively. Recent studies have found a spatially extended GeV source within the virial radius, consistent with the internal shock origin. Here we report the detection of a new GeV source at a distance of about 2.8$^\circ$ from the center of the Coma cluster through the analysis of 16.2 years of Fermi-LAT data. The hard spectrum of the source, in agreement with the ICS origin, and its location in a large-scale filament of galaxies points to the external accretion shock origin. The gamma-ray ($0.1-10^3$ GeV) luminosity of the source, $1.4\times 10^{42}~ {\rm erg~s^{-1}}$, suggests that a fraction $\sim 10^{-3}$ of the kinetic energy flux through the shock-surface is transferred to relativistic CR electrons. |
| Databáze: |
arXiv |
| Externí odkaz: |
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