North Polar Spur šaxâk-e kahkešâni-ye hudari Fr.: éperon galactique nord One of the largest coherent structures in the radio sky, projecting from the → Galactic plane at → Galactic longitudel ~ 20° and extending to a very high → Galactic latitudeb ~ +80°. It was first identified in low frequency → radio surveys in the 1950s. The spur is also prominent in → soft X-rays. Its origins and nature have long been debated. However, what causes this phenomena is not well understood. It may be due to a combination of → OB associations and → supernova explosions. |