The contribution of solar-wind ions exchanging electrons with helium and hydrogen near the Sun is shown to be only about 40 per cent of the 1/4-keV X-ray flux observed in the Galactic plane; this supports the existence of a local ‘hot bubble’ filled with X-ray-emitting gas, accounting for the rest of the flux.
- M. Galeazzi
- M. Chiao
- B. M. Walsh