Experimental Seminars

The origin of the very high energy cosmic rays in the central 100 pc of our Galaxy

by Dr Léa JOUVIN (APC Paris)

Europe/Madrid
IFAE Seminar Room

IFAE Seminar Room

Description
The Galactic center (GC) is a very rich and complex astrophysical region. The high supernovae (SN) rate associated with the strong massive star formation should create a sustained cosmic rays (CRs) injection in the GC via the shocks they produce. The region also harbors a Super-Massive Black Hole (SMBH) of 4 * 106 Msun, named Sgr A*. Since it has been argued that the SMBH might also accelerate particles up to very high energies (VHE), its current and past activity could contribute to the CR population. In 2006, the H.E.S.S. collaboration revealed the presence of a VHE diffuse emission in the inner 100 pc of the Galaxy in close correlation with the molecular matter spread in the central molecular zone (CMZ). A major part of the emission is thus certainly of hadronic origin but it still remains mysterious. I will report a new detailed spectral and morphological analysis of this region using 10 years of H.E.S.S. observations as well as a detailed modelling of the gamma-ray emission induced by the SNs. I will show the impact of the spatial and temporal distribution of SNs in the CMZ on the VHE emission morphology and spectrum. A peaked gamma-ray profile and CR excess towards the GC, can be obtained using realistic SN spatial distribution taking into account the central massive star clusters. A strong dependence on the morphology of the emission with the energy is expected in this scenario. The CR density profile can also be reproduced by a unique stationary injection at the center by Sgr A* but it implies a stable morphology across the energy range. To distinguish the models, we need new high level analysis tool to study the evolution of this emission with the energy. I will finish by presenting these new tools that will be also necessary to analyse the data of the futur telescope CTA. In particular, I will detail the 3D analysis that I implemented in the software Gammapy to fit simultaneously a spectral and a morphological shape on a data cube.
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