Obtaining the diffusion coefficient for cosmic ray propagation in the Galactic Centre Ridge through time-dependent simulations of their gamma-ray emission
arXiv:0812.0575 · doi:10.1016/j.astropartphys.2008.11.001
Abstract
Recent observations by the H.E.S.S. collaboration of the Galactic Centre region have revealed what appears to be gamma-ray emission from the decay of pions produced by interactions of recently accelerated cosmic rays with local molecular hydrogen clouds. Synthesizing a 3-D hydrogen cloud map from the available data and assuming a diffusion coefficient of the form kappa(E) = kappa_0(E/E0)^delta, we performed Monte Carlo simulations of cosmic ray diffusion for various propagation times and values of kappa_0 and delta. By fitting the model gamma-ray spectra to the observed one we were able to infer the value of the diffusion coefficient in that environment (kappa = 3.0 +/- 0.2 kpc^2 Myr^-1 for E = 10^12.5 eV and for total propagation time 10^4 yr) as well as the source spectrum (2.1 < gamma < 2.3). Also, we found that proton losses can be substantial, which justifies our approach to the problem.
7 pages, 7 figures, accepted for publication in Astroparticle Physics
References in corpus (8)
- Cosmic-ray propagation and interactions in the Galaxy
- Discovery of Very-High-Energy Gamma-Rays from the Galactic Centre Ridge
- Interactions of Cosmic Ray Nuclei
- Dense Ionized and Neutral Gas Surrounding Sgr A*
- Self-Consistent Particle Acceleration in Active Galactic Nuclei
- Gamma Rays frim the Galactic Centre
- The H.E.S.S. View of the Central 200 Parsecs
- Simulation of Cosmic Ray propagation in the Galactic Centre Ridge in Accordance with Observed VHE gamma-ray Emission
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- Gamma rays from the Galactic Centre region: a review
- Hadronic origin of multi-TeV gamma rays and neutrinos from low-luminosity active galactic nuclei: implications of past activities of the Galactic center
- Fermi bubble edges: spectrum and diffusion function