A Markov Chain Monte Carlo for Galactic Cosmic Ray physics: I. Method and results for the Leaky Box Model
| dc.creator | Putze, A. | |
| dc.creator | Derome, L. | |
| dc.creator | Maurin, D. | |
| dc.creator | Perotto, L. | |
| dc.creator | Taillet, R. | |
| dc.date | 2008-08-18 | |
| dc.date | 2009-01-21 | |
| dc.date.accessioned | 2026-07-07T13:13:51Z | |
| dc.date.available | 2026-07-07T13:13:51Z | |
| dc.description | Propagation of charged cosmic-rays in the Galaxy depends on the transport parameters, whose number can be large depending on the propagation model under scrutiny. A standard approach for determining these parameters is a manual scan, leading to an inefficient and incomplete coverage of the parameter space. We implement a Markov Chain Monte Carlo (MCMC), which is well suited to multi-parameter determination. Its specificities (burn-in length, acceptance, and correlation length) are discussed in the phenomenologically well-understood Leaky-Box Model. From a technical point of view, a trial function based on binary-space partitioning is found to be extremely efficient, allowing a simultaneous determination of up to nine parameters, including transport and source parameters, such as slope and abundances. Our best-fit model includes both a low energy cut-off and reacceleration, whose values are consistent with those found in diffusion models. A Kolmogorov spectrum for the diffusion slope (delta=1/3) is excluded. The marginalised probability-density function for delta and alpha (the slope of the source spectra) are delta~0.55-0.60 and alpha~2.14-2.17, depending on the dataset used and the number of free parameters in the fit. All source-spectrum parameters (slope and abundances) are positively correlated among themselves and with the reacceleration strength, but are negatively correlated with the other propagation parameters. A forthcoming study will extend our analysis to more physical diffusion models. | |
| dc.description | 18 pages, 15 figures, one brief section 2 added on the method (matches the A&A accepted version) | |
| dc.identifier | https://arxiv.org/abs/0808.2437 | |
| dc.identifier | http://arxiv.org/abs/0808.2437 | |
| dc.identifier | A&A 497, 991 (2009) | |
| dc.identifier | doi:10.1051/0004-6361/200810824 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/230024 | |
| dc.subject | Astrophysics | |
| dc.title | A Markov Chain Monte Carlo for Galactic Cosmic Ray physics: I. Method and results for the Leaky Box Model | |
| dc.type | text |