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The high SNR rate in the Galactic Center: origin of the cosmic rays excess?

Published online by Cambridge University Press:  09 February 2017

L. Jouvin
Affiliation:
APC, UMR 7164, CNRS, Université Paris VII, CEA, Observatoire de Paris, Paris email: lea.jouvin@apc.in2p3.fr
A. Lemière
Affiliation:
APC, UMR 7164, CNRS, Université Paris VII, CEA, Observatoire de Paris, Paris email: lea.jouvin@apc.in2p3.fr
R. Terrier
Affiliation:
APC, UMR 7164, CNRS, Université Paris VII, CEA, Observatoire de Paris, Paris email: lea.jouvin@apc.in2p3.fr
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Abstract

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The center of our Galaxy hosts a Super-Massive Black Hole (SMBH) of about 4 × 106 M. Since it has been argued that the SMBH might accelerate particles up to very high energies, its current and past activity could contribute to the population of Galactic cosmic-rays (CRs). Additionally, the condition in the Galactic Center (GC) are often compared with the one of a starburst system. The high supernovae (SN) rate associated with the strong massive star formation in the region must create a sustained CR injection in the GC via the shocks produced at the time of their explosion.

The presence of an excess of very high energy (VHE) cosmic rays in the inner 100 pc of the Galaxy in close correlation with the massive gas complex known as the central molecular zone (CMZ) has been revealed in 2006 by the H.E.S.S. collaboration. Recently, by analysing 10 years of H.E.S.S. data, the H.E.S.S. collaboration confirmed the presence of this extended VHE diffuse emission and deduced a CR density peaked toward the GC. The origin of the CR over-abundance in the GC still remains mysterious: Is it due to a single accelerator at the center or to multiple accelerators filling the region?

In order to investigate the presence of these multiple CR accelerators, and in particular the impact of their spatial distribution on the VHE emission morphology, we build a 3D model of CR injection and diffusive propagation with a realistic 3D gas distribution. We discuss the CR injection in the region by a spectral and morphological comparison with H.E.S.S. data.

We show that a peaked γ-ray profile towards the GC center is obtained using a realistic SN spatial distribution taking into account the central massive star clusters. The contribution of theses sources cannot be neglected in particular at high longitudes. In order to fit the very central excess observed with H.E.S.S., another central VHE component is probably necessary.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2017 

References

Abramowski, A., et al., 2016, Nature, 531, 476 Google Scholar
Aharonian, F., 2004 Google Scholar
Ponti, G., et al., MNRAS, 453, 172 Google Scholar
Aharonian, F., et al. 2006, Nature 439 695698 Google Scholar
Ghez, A. M., et al. 2008, ApJ 689 10441062 Google Scholar
Wang, Q. D., et al. 2013, Science 341 981983 Google Scholar
Liu, S., et al. 2006, ApJ 647 10991105 Google Scholar
Crocker, R. M., et al. 2011, MNRAS 413 763788 Google Scholar
Macias, O., et al. 2014, Arxiv e-printsGoogle Scholar
Mauerhan, J. C., et al. 2010, ApJ 725 188199 Google Scholar
Najarro, F., et al. 2004, ApJ 611 L105-L108 Google Scholar
Liu, H. B., et al. 2013, ApJ, 770, 44 Google Scholar
Figer, , et al. ApJ, 525, 750 Google Scholar
Sawada, T., et al. 2004, MNRAS 349 11671178 Google Scholar
Jouvin, L., et al. 2016, MNRAS, submittedGoogle Scholar