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Poster communications

A Markov Chain Monte Carlo technique for Galactic cosmic-ray physics

Abstract : We implemented a Markov Chain Monte Carlo technique to estimate the probability-density functions of the cosmic-ray transport and source parameters in a diffusion model. From the measurement of the B/C ratio and radioactive cosmic-ray clocks, we calculate their probability density functions, with a special emphasis on the halo size L of the Galaxy and the local underdense bubble of size rh . The B/C analysis leads to a most probable diffusion slope δ = 0.86+0.04 for a diffusion model including convection and reacceleration. A combined fit -0.04 on B/C and the isotopic ratios (10 Be/9 Be, 26 Al/27 Al, 36 Cl/Cl) leads to L = 8+8 kpc and -7 rh = 120+20 pc. This value for rh is consistent with direct measurements of the local interstellar -20 medium. The size of the diffusive halo depends crucially on the value of the diffusion slope δ, and also on the presence/absence of the local underdensity damping effect on radioactive nuclei.
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Contributor : Emmanuelle Vernay <>
Submitted on : Thursday, July 22, 2010 - 9:04:47 AM
Last modification on : Thursday, November 19, 2020 - 12:58:40 PM



A. Putze, D. Maurin, L. Derome. A Markov Chain Monte Carlo technique for Galactic cosmic-ray physics. 38th COSPAR Scientific Assembly (Cospar10), Jul 2010, Bremen, Germany. ⟨in2p3-00504946⟩



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