Abstract
We model the transport of cosmic ray nuclei in the galaxy by means of a new numericalcode. At variance with previous numerical models, ours accounts for a generic spatialdistribution of the diffusion coefficient. We found that in the case of radially uniformdiffusion, the main secondary/primary ratios (B/C, N/O and sub-Fe/Fe) and themodulated antiproton spectrum consistently match the available observations. Convectionand re-acceleration do not seem to be required in the energy range that we consider:1≤E≤103 GeV/nucleon. We generalize these results, accounting for radial dependence of the diffusion coefficient,which is assumed to trace that of the cosmic ray sources. While this does not affect theprediction of secondary/primary ratios, the simulated longitude profile of the diffuseγ-ray emission is significantly different from that for the uniform case and may agree withEGRET measurements without requiring invoking ad hoc assumptions on the galactic gasdensity distribution.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have