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Volume 358 - 36th International Cosmic Ray Conference (ICRC2019) - CRD - Cosmic Ray Direct
A Novel Analytical Model of the Magnetic Field Configuration in the Galactic Center Explaining the Diffuse Gamma-Ray Emission
M. Guenduez,* J. Becker Tjus, K. Ferrière, R.J. Dettmar, D. Bomans
*corresponding author
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Pre-published on: 2019 August 20
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Reliable identification of the origin of the high-energy non-thermal emission from the Galactic Center (GC) is not achievable without adequate consideration of the ambient conditions such as the magnetic field configuration or gas distribution. In a first step, we present a model that can explain the diffuse gamma-ray emission as measured by H.E.S.S. for small longitudes in the Galactic Center region but comes to grief with higher longitudes. The model is given via the solution of a transport equation that allows for a radial dependency of the mass distribution. In order to move from this semi-analytical approximation toward a full understanding of the PeVatron signature, we present a new 3D analytical model of the gas distribution in the Central Molecular Zone (CMZ). Furthermore, we derive for the first time a 3D model of the magnetic field configuration and strength in the CMZ, which is analytical and divergence-free. The model is built via a combination of a model for the diffuse inter-cloud medium, local molecular clouds and non-thermal filaments at which local information are based on investigations from previous works and the molecular gas density. It can be shown that without an efficient longitudinal CR entrapment, a single source at the center does not facilely suffice the diffuse gamma-ray detection. Further, we show that the new magnetic field model \textit{GBFD19} is compatible with recent polarization data and has a significant impact on the longitudinal profiles of CR propagation.
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