SOFT X-RAYS AND COSMIC GAMMA-RAYS

The manner in which cosmic ray particles accelerate and propagate in the Galaxy, and beyond, is still in doubt, although a Galactic origin for the bulk of the particles is very probable, this knowledge having come from a study of cosmic gamma-rays in the energy range 30-1000 MeV. Below 240 eV there is another cosmic component, that of soft X-rays, which is also of uncertain origin. Remarkably, we find that there is a strong correlation of the two; most noticeably, the 'cosmic ray intensity', inferred from the gamma-ray intensity divided by the column density of gas along each line of sight, correlates strongly with the strength of the X-ray signal, particularly away from the Galactic plane. Although it is just possible that there is far more ionized gas in the local region of the Galaxy than had been realized, it is more likely that the cosmic ray intensity is higher in parts of the local 'bubble' than elsewhere.