Soft X-ray emission from radio Loops I and III compared

We examine X-ray maps of the whole sky covering energies from 0.1 to 6 keV. We model Loop I X-ray emission as being caused by an old supernova that exploded into an already warm interstellar medium. After comparison with Loop III we deduce that there may be a general temperature gradient in the gas as we move away from the plane in the northern galactic hemisphere.