Speaker
Dr
Antje Putze
(Oskar Klein Center (Stockholm University))
Description
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 r_h. We also
derive the mean, best-fit model parameters and 68% confidence level for the various
parameters, and the envelopes of other quantities. Finally, we check the
compatibility of the primary fluxes with the transport parameters derived from the
B/C analysis and then derive the source parameters (slope, abundance, and low-energy
shape). We conclude that the size of the diffusive halo depends on the
presence/absence of the local underdensity damping effect on radioactive nuclei.
Models based on fitting B/C are compatible with primary fluxes. The different
spectral indices for the propagated primary fluxes up to a few TeV/n can be naturally
ascribed to transport effects only, implying universality of elemental source
spectra. The analysis relies on the public USINE package which deals with the
propagation of Galactic cosmic-ray nuclei (all existing nuclei) and antinuclei
(antiprotons and antideuterons) in various models (Leaky-Box and diffusion models).
Primary author
Dr
Antje Putze
(Oskar Klein Center (Stockholm University))
