Gamma-ray afterglow from galactic centre gas clouds reveals prehistoric particle accelerator

The top panel shows the gamma-ray image of the Galactic centre region taken by H.E.S.S. Two bright sources dominate the view: HESS J1745-290, a mysterious source right at the centre of the Galaxy; and, about 1 degree away, the gamma-ray supernova remnant G 0.9+0.1. The lower panel shows the same image with the bright sources subtracted. In this image, gamma-ray emission extending along the plane is visible as well as another mysterious source: HESS J1745-303. The dashed lines show the position of the Galactic plane. The white circles show the positions from which the two sources were removed. Image: H.E.S.S Cooperation